feat: show reels in the profile grid, as Instagram does

The Posts tab filtered reels out, so the grid was not the archive — it
was the archive minus its videos. For `for.heejin` that hid 533 of 1225
posts; for `loonatheworld`, 1100 of 3813. On Instagram the grid holds
everything and the Reels tab is a filtered view of that same set.

Extract the tab logic to src/lib/post-tabs.ts so the reel heuristic is
testable outside the component, and add dedupePostCopies: the jd2 flow
crawls the profile URL and the /reels URL separately because the profile
page misses some reels, so the two overlap and a reel can land on disk
twice. Those are two posts with distinct directory-scoped ids, which the
grid would now render side by side; the reels-source copy wins so the
survivor is still recognised as a reel.

Deciding what *is* a reel stays a guess for most archives. Instagram
marks it with product_type ("clips" vs "feed" vs "igtv" — all three are
GraphVideo, and aspect ratio does not separate them), but only newer
Instaloader captures carry it: 1101 of gibiofficial's 5919 sidecars, and
only 2 marked clips. JDownloader archives carry none, so those still
fall back to treating a lone video as a reel.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

.dockerignore

@@ -1,5 +1,6 @@
 node_modules
 dist
+dist-server
 .git
 .github
 _sample-archives

.gitignore

@@ -1,6 +1,7 @@
 node_modules/
 build/
 dist/
+dist-server/
 coverage/
 .DS_Store
 *.log

CLAUDE.md

@@ -0,0 +1,151 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Project Overview
+
+InstaArchive Viewer is a React 19 + Vite 6 PWA for browsing archived Instagram data (official Instagram exports and Instaloader archives). All archive *parsing* happens client-side in the browser; the Express backend only indexes and serves files from disk, and never parses archive contents.
+
+## Commands
+
+- `npm install` — install dependencies
+- `npm run dev` — Vite dev server on port 3000 (proxies `/api` and `/archives` to `http://localhost:3001`)
+- `npm run server` — Express backend (`tsx server.ts`) on port 3001, serving `ARCHIVES_DIR` (defaults to `./_sample-archives`)
+- `npm run build` — frontend to `dist/`, backend to `dist-server/`
+- `npm run lint` — type-check only (`tsc --noEmit`)
+- `npm test` / `npm run test:watch` — vitest
+- `npx vitest run src/lib/archive-patterns.test.ts` — a single test file
+- `npm run jd2 -- --archives <dir> --dry-run` — generate JDownloader `.crawljob`
+  files for every profile on disk (see `scripts/jd2-sync.ts` and
+  `docs/jdownloader.md`)
+
+Local development usually needs both `npm run dev` and `npm run server`. Local-folder mode works without the backend; server-mode archives do not.
+
+## Architecture
+
+### Two archive sources, one data model
+
+Loading is unified behind the `ArchiveFile` interface (`src/types/index.ts`, implementations in `src/lib/archive-files.ts`):
+
+- **`LocalArchiveFile`** — wraps a browser `File`. `createObjectUrl()` mints a **disk-backed** blob URL directly from the File; never route media through `arrayBuffer()`, which pulls whole files into memory.
+- **`RemoteArchiveFile`** — wraps a file served from `/archives/...`, fetched on demand.
+
+`revocable` tells callers whether the returned URL must be revoked. The scanner tracks every minted URL and releases them on archive teardown.
+
+### Sidecar directories
+
+An archive root holds one directory per profile plus *sidecars* that belong to it:
+
+```
+4utumn07                                 -> posts (base)
+4utumn07 - reels                         -> reels
+story - 4utumn07                         -> stories
+story highlights - 4utumn07 - Sunstory   -> highlight "Sunstory"
+```
+
+`src/lib/archive-grouping.ts` (shared by server and tests) folds these into a single profile with a `sources` list. Sidecars never appear as standalone archives. Each file the server returns carries its `kind`, so the client routes posts / reels / story ring / highlight circles without re-deriving naming rules.
+
+### Server-side archive index (`src/lib/archive-index.ts`)
+
+**Do not reintroduce per-request filesystem walks.** Archives typically live on network storage where per-file `stat` costs ~1.4ms and does not parallelise; a naive walk of a 110k-file root took ~52s per listing. Instead:
+
+- Each source directory is indexed once and cached, keyed by its **directory mtime** (a directory `stat` is effectively free).
+- The index is warmed in the background at startup and persisted to `CACHE_DIR` (mount a volume at `/cache`).
+- `GET /api/archives` does no file walking at all — it returns directory-mtime `signature`s, which the client uses for cache invalidation instead of a file count.
+- Only media files are stat'd (for `size`, which gates thumbnailing) and only highlights need `mtime` (their filenames carry no date).
+
+### Scanning pipeline (`src/hooks/useArchiveScanner.ts`)
+
+`handleFiles` indexes files, detects format, then parses via one of three largely independent paths that all write into a shared `postsMap`:
+
+1. **JSON manifest** (`posts_1.json`, possibly `.json.xz` via `xz-decompress`) — media matched to entries by URI, then ID, then filename heuristic, in that fallback order.
+2. **Filename patterns** — see `src/lib/archive-patterns.ts` for the export / Instaloader / highlight regexes, extracted as pure functions and covered by tests. Prefer changing them there.
+3. **Generic grouping fallback** — when nothing else matched, files sharing a basename become one carousel.
+
+Results are cached to IndexedDB. Media records store a stable `path`; **`url` is not persistable** for local archives because blob URLs die with the document.
+
+### Cache and local-archive persistence (`src/lib/archive-cache.ts`)
+
+IndexedDB keys are namespaced (`archive:`, `thumb:`, `handle:`) so listing archives does not deserialize every cached thumbnail blob, and thumbnails are scoped per archive to avoid cross-archive collisions.
+
+Restoring an archive **rehydrates URLs from `path`**: server archives rebuild HTTP URLs; local archives re-open a persisted `FileSystemDirectoryHandle` and mint fresh blob URLs. If the folder is unreachable (permission lapsed, or the browser lacks `showDirectoryPicker` — Firefox/Safari), the app re-prompts rather than rendering broken images.
+
+### Thumbnails (`src/hooks/useThumbnailQueue.ts` + `src/lib/thumbnail-worker.ts`)
+
+Images over 1MiB are downscaled in a Web Worker via `OffscreenCanvas`. The queue is **serial on purpose** — decoding several 50MP+ images at once OOMs the tab. `requestThumbnail` must keep a stable identity (it reads cache state through a ref), or every completed thumbnail re-runs the effect in all mounted thumbnails.
+
+### Profile tabs (`src/lib/post-tabs.ts`)
+
+The grid holds **everything**, reels included, and the Reels tab is a *filtered view* of that same set — as on Instagram. Only the Reels tab filters. The tabs were mutually exclusive until v1.7.0, which hid a lot: 1100 of `groupfandom`'s 3813 posts and 533 of `for.member`'s 1225 never appeared in the grid at all.
+
+Deciding *what is a reel* has no good answer for most archives. Instagram's own marker is `product_type` on the post's GraphQL node (`clips` = reel, `feed` = ordinary feed video, `igtv`, `story`) — `__typename` is `GraphVideo` for all three, and aspect ratio does not separate them either. But:
+
+- Only Instaloader archives carry that metadata, and only newer captures. A survey of `hazelofficial` found `product_type` on 1101 of 5919 sidecars, and just **2** posts marked `clips`.
+- JDownloader archives carry none at all — media plus a `.txt` holding the bare caption.
+
+So the viewer believes a `- reels` sidecar directory when one exists, and otherwise falls back to treating a lone video as a reel. **The fallback is a guess**: it cannot tell a reel from a feed video or an old IGTV upload, and it misses videos inside carousels.
+
+`dedupePostCopies` exists because the JDownloader flow crawls the profile URL and the `/reels/` URL separately (the profile page misses some reels), so the two overlap and a reel can land on disk twice. Those become two posts with distinct directory-scoped ids, which the grid would otherwise render side by side. It dedupes by shortcode, preferring the reels-source copy. It is only safe over `allPosts` — stories and highlights are excluded there, and a shortcode may legitimately appear in both a profile and a highlight.
+
+### URL state (`src/App.tsx`, `src/lib/routing.ts`)
+
+Paths mirror Instagram: `/<archive>/`, `/<archive>/reels/`, `/<archive>/p/<shortcode>/`. The old `?a=&t=&p=` form is still parsed for existing links but never written. Reserved prefixes (`api`, `archives`, `assets`…) can't be mistaken for a profile name.
+
+A post URL carries no tab, as on Instagram — the tab is re-derived from the post's `source`, so a reel link lands on the Reels tab and pages through reels. Sidecar posts keep directory-scoped ids internally but expose only the shortcode.
+
+Three rules, all learned from real bugs:
+
+- The initial route is captured into a ref on first render; the URL is rewritten from state as soon as anything loads, so reading `window.location` later sees the rewrite, not the user's link.
+- URL writing is gated on `hasInitialLoaded`, otherwise it erases the deep link before the loader consumes it.
+- Deep-link resolution waits on the archive fetch having *settled* (`archivesFetched`), not on `isServerMode`, which is still false while the request is in flight.
+
+### Mobile feed (`src/components/PostFeed.tsx`)
+
+Below `md`, opening a post renders a scrolling feed page rather than the modal (`useIsMobile` decides). Only a window of posts is mounted; it grows both ways, and prepending corrects `scrollTop` in a `useLayoutEffect` so content doesn't jump. Only the post crossing the viewport centre plays its video and drives the URL. Desktop keeps `PostModal`; both share `MediaCarousel`.
+
+### Backend (`server.ts`)
+
+Serves `/api/archives`, `/api/archives/:name/files`, static `/archives`, and the built SPA. Notes:
+
+- Express decodes route params **after** segment matching, so `..%2f` reaches the handler as `../`. All user-supplied archive names go through `resolveArchivePath`.
+- `os.userInfo()` throws for a UID with no `/etc/passwd` entry, which is what `--user 1234:1234` produces — use `describeUser()`.
+
+### CSP: do not tighten `script-src` or `connect-src` without testing xz
+
+The xz decompressor for Instaloader `.json.xz` sidecars is **WebAssembly**, embedded as a `data:` URL the library fetches at startup. The policy must keep:
+
+```
+script-src  'self' 'wasm-unsafe-eval'     // compile wasm, without allowing eval() of JS
+connect-src 'self' data:                  // fetch the embedded module
+```
+
+Removing either breaks decoding with a bare `TypeError: Failed to fetch` **and no stack** — it surfaces through `new Response(stream).json()`, so it reads like a network fault rather than a policy block. The visible symptom is not an error page: archives silently lose captions, story flags and all profile metadata (follower counts, bio, name). This shipped broken for several releases.
+
+To check quickly, run in the page console:
+
+```js
+await fetch('data:application/wasm;base64,AGFzbQEAAAA=')            // connect-src
+await WebAssembly.instantiate(Uint8Array.of(0,97,115,109,1,0,0,0))  // script-src
+```
+
+**The Vite dev server does not send these headers**, so anything CSP-related is invisible in `npm run dev`. Verify security-header and PWA behaviour by building and serving `dist/` through `server.js`, not against the dev server.
+
+### PWA: server-only changes do not reach installed clients
+
+The service worker precaches `index.html` **together with its response headers**. A change that touches only the server (a CSP fix, a new header) leaves the client build byte-identical, so the precache manifest and `sw.js` are unchanged, the worker never updates, and installed clients keep replaying the old shell with the old headers — indefinitely.
+
+`vite.config.ts` therefore compiles the package version into the client via `define: { __APP_VERSION__ }`, and `App.tsx` renders it in the footer. That is **load-bearing**: it makes every release change the bundle hash → `index.html` → its precache revision → `sw.js`, which is what browsers byte-compare to decide whether to update. Don't remove it as dead weight.
+
+To recover a client stuck on an old shell: unregister the service worker, delete its caches, reload.
+
+### Deployment
+
+Live archives live in `<share>/Instagram-archive/archives/` — one directory per profile plus sidecars. Directories that are not Instagram profiles (tool output, exports from other services) sit *outside* that folder so they never reach the viewer.
+
+Container runs as non-root. The image defaults to `node`, but the archive share must be *listable* by that UID — a mode-711 share owned by another account needs `user: "<uid>:<gid>"` in compose. Mount a volume at `/cache` so the index survives restarts.
+
+### PWA / build quirks
+
+- `vite.config.ts` sets `hmr: process.env.DISABLE_HMR !== 'true'` — intentional, leave it.
+- `workbox.navigateFallbackDenylist` excludes `/api` and `/archives` so those hit the real server.
+- Fonts and icons are vendored in `public/` — do not reintroduce CDN references; the app advertises offline support and local-only processing.

Dockerfile

@@ -18,6 +18,9 @@ FROM node:20-slim AS runtime
 ENV NODE_ENV=production
 ENV PORT=3000
 ENV ARCHIVES_DIR=/archives
+# Where the archive index is persisted; mount a volume here so a restart does
+# not have to re-walk the whole archive root.
+ENV CACHE_DIR=/cache
 
 WORKDIR /app
 
@@ -25,12 +28,16 @@ WORKDIR /app
 COPY package*.json ./
 RUN npm ci --omit=dev
 
-# Copy built assets and server
+# Copy built assets and server. The whole dist-server tree is needed: the
+# server imports shared archive-grouping logic emitted alongside it.
 COPY --from=build /app/dist ./dist
-COPY --from=build /app/dist-server/server.js ./server.js
+COPY --from=build /app/dist-server/ ./
 
-# Ensure archives directory exists
+# Ensure archives and cache directories exist, writable by the runtime user.
-RUN mkdir -p /archives
+RUN mkdir -p /archives /cache && chown node:node /cache
+
+# Drop root: the server reads the archives volume and writes only its index.
+USER node
 
 EXPOSE 3000
 

GEMINI.md

@@ -5,37 +5,65 @@
 **InstaArchive** is a high-performance, React-based Progressive Web App (PWA) designed to browse and explore archived Instagram data with a native-feeling interface. It supports both local directory loading and self-hosted server modes.
 
 ### Key Technical Features
-- **Persistent Caching:** Uses `idb-keyval` (IndexedDB) to cache parsed metadata and server-side media URLs. Subsequent loads of the same archive are instant.
+- **Permalinks:** Full synchronization between application state and URL query parameters (`?a=`, `?t=`, `?p=`). Supports deep-linking to archives, tabs, and specific posts. URL parameters are automatically cleaned when navigating back to the archive explorer.
-- **Glassy Scanner UI:** A custom-built glassmorphism scanning dashboard with throttled (1s) dynamic blurred backgrounds and a high-density system log.
+- **Persistent Caching:** Uses `idb-keyval` (IndexedDB) to cache parsed metadata. Subsequent loads are near-instant.
-- **Support for Multiple Formats:** Recognizes official Instagram export structures and Instaloader regex-based naming conventions.
+  - **Metadata:** Caches profile info and post lists for both remote AND local archives.
-- **Compressed Metadata:** Support for `.json.xz` file decompression using `xz-decompress` (WASM-powered).
+  - **Thumbnails:** High-res images (>1MiB) and videos have thumbnails generated and cached in IndexedDB with the `thumb_` prefix.
-- **Navigation Protection:** Intercepts browser history (`popstate`) and exit events (`beforeunload`) to prevent session loss while maintaining a "Back to Explorer" SPA flow.
+- **Background Media Processing:**
-- **Production-Ready Docker:** Multi-stage Docker builds using `node:slim` to serve both the Express API and the Vite-built frontend.
+  - **High-Res Images:** A dedicated Web Worker (`thumbnail-worker.ts`) handles image resizing using `OffscreenCanvas` and `createImageBitmap` to prevent main-thread jank.
+  - **Serial Queue:** A memory-safe queue ensures only one high-res image is decoded at a time, preventing Out-of-Memory (OOM) crashes on 50MP+ files.
+- **High-Performance Carousel:** Advanced `PostModal` with:
+  - **Inter-Post Preloading:** Preloads the first media of adjacent posts for instant navigation.
+  - **Intra-Carousel Preloading:** Intelligently preloads the current carousel's slides.
+  - **Seamless Transitions:** Zero-latency slide transitions without "black flashes" between images.
+- **Glassy Scanner UI:** Custom-built glassmorphism scanning dashboard with double-buffering logic to ensure smooth, flicker-free background crossfades during file indexing.
+- **PWA Capabilities:** 
+  - **Auto-Updates:** Hourly periodic update checks.
+  - **Navigation Fix:** `navigateFallbackDenylist` allows direct server access to `/archives/` and `/api/` (enabling "Open in new tab" for original files).
 
 ### Main Technologies
-- **Frontend:** React 19, Vite, TypeScript
+- **Frontend:** React 19, Vite 6, TypeScript
 - **Styling:** Tailwind CSS (v4)
 - **Icons:** Lucide React
 - **Animations:** Framer Motion (`motion/react`)
 - **Persistence:** IndexedDB (`idb-keyval`)
-- **Backend:** Express, tsx (for server-side scanning)
+- **Backend:** Express, tsx
-- **Decompression:** xz-decompress (WASM)
+- **Workers:** Web Workers for background image processing.
+
+## Architecture
+
+### State Management
+- **`useArchiveScanner` Hook:** Centralized logic for parsing and caching. It handles folder-name-to-username detection and "Smart Fallback" profile pictures (using the oldest image if no profile pic is found).
+- **`useThumbnailQueue` Hook:** Manages the serial processing of high-resolution media.
+
+### Cache Schema
+```typescript
+interface CacheData {
+  name: string;
+  isLocal: boolean;
+  fileCount: number;
+  posts: Post[];      // Cached for all archive types
+  stories: Post[];
+  profileMetadata: {
+    username: string;
+    fullName: string;
+    bio: string;
+    followerCount: number;
+    followingCount: number;
+    externalUrl: string;
+    profilePic: string | null;
+    allProfilePics: string[];
+  };
+  timestamp: number;
+}
+```
 
 ## Commands
-- `npm install`: Install project dependencies.
+- `npm install`: Install dependencies.
-- `npm run dev`: Start the local development server on port 3000.
+- `npm run dev`: Start dev server (Port 3000).
-- `npm run build`: Generate the production-ready build in the `dist` folder.
+- `npm run build`: Build frontend (`dist/`) and server (`dist-server/`).
-- `npm run server`: Start the backend server to scan `./_sample-archives`.
+- `npm run server`: Start production-ready backend.
 - `npm run lint`: Execute TypeScript type-checking.
 
 ## Production Deployment
-The project is containerized and available on GHCR. It expects a volume mount at `/archives` containing subdirectories for each user.
+The project is containerized. It expects a volume mount at `/archives` containing subdirectories for each user.
-
-### Key Environment Variables
-- `PORT`: Server port (default: 3000)
-- `ARCHIVES_DIR`: Path to the archives collection (default: /archives)
-
-## Development Conventions
-- **Username Logic:** The directory name is the definitive source of truth for the account username.
-- **State Management:** React `useState`, `useMemo`, and `useCallback` for optimized performance.
-- **File Handling:** Uses `RemoteArchiveFile` and `LocalArchiveFile` classes to provide a unified `ArchiveFile` interface for the parser.

README.md

@@ -4,12 +4,16 @@ A high-performance React PWA for browsing archived Instagram data with a native-
 
 ## Features
 
-- **Persistent Caching**: Uses IndexedDB to store parsed archives locally. Subsequent loads are near-instant.
+- **Advanced Carousel**: Seamless, zero-latency transitions between slides with intelligent preloading. Navigating between different posts is now near-instant thanks to inter-post background preloading.
-- **Glassy Scanning UI**: A modern, translucent white terminal experience with a dynamic blurred background of your media.
+- **High-Res Performance**: Handles 50MP+ images effortlessly using a background Web Worker and a memory-safe serial processing queue.
-- **Local Privacy**: All processing is done client-side. Even when using the self-hosted version, your media is processed locally in your browser.
+- **Persistent Local Caching**: Uses IndexedDB to store parsed archives and generated thumbnails. **Local folders** now load instantly from cache on return visits without needing to re-upload files.
-- **Multiple Formats**: Supports official Instagram JSON exports and Instaloader regex-based naming conventions.
+- **Permalinks**: State is synchronized with the URL, allowing you to share direct links to archives, tabs, or specific posts. Navigating back to the explorer cleans up URL parameters automatically.
-- **Story Viewer**: Native-like story experience with segmented progress bars, auto-playback, and audio controls.
+- **Glassy Scanning UI**: A refined, translucent white terminal experience with flicker-free, double-buffered dynamic blurred backgrounds.
+- **PWA with Auto-Update**: Fully offline-capable and installable. Clients automatically receive updates when a new version is deployed to the server.
+- **Local Privacy**: All processing is done client-side. Even when using the self-hosted version, your media is processed locally in your browser and never uploaded.
+- **Smart Fallbacks**: Automatically detects usernames from folder names and uses the oldest archive image as a profile picture if one is missing.
 - **Customizable Grid**: 1:1 or 3:4 aspect ratios with adjustable "bumps" for aesthetic alignment.
+- **Story Viewer**: Native-like story experience with segmented progress bars, auto-playback, and audio controls.
 - **Navigation Protection**: Intercepts accidental browser "Back" or "Refresh" actions to protect your current session.
 
 ## Deployment
@@ -25,6 +29,8 @@ docker run -d \
   ghcr.io/ergosteur/instaarchive-viewer:latest
 ```
 
+> **Note for Linux/SELinux users:** If you see "Permission Denied" in the logs, append `,z` to your volume mount: `-v /path/to/archives:/archives:ro,z`
+
 ### Docker Compose
 
 Create a `compose.yml` file:
@@ -36,13 +42,39 @@ services:
     ports:
       - "3000:3000"
     volumes:
-      - ./archives:/archives:ro
+      - ./archives:/archives:ro,z # ,z handles SELinux permissions
 ```
 
-Run with:
+### Troubleshooting Permissions
-```bash
+
-docker compose up -d
+If the app shows "No Archives Found" and logs `EACCES: permission denied`:
-```
+
+1. **Check Directory Permissions**: Ensure the archive folder is world-readable:
+   ```bash
+   chmod -R 755 /path/to/archives
+   ```
+2. **SELinux (Fedora/RHEL/CentOS)**: Use the `:z` flag in your volume mount as shown above.
+3. **User Mapping**: The container runs as the non-root `node` user (UID 1000).
+   If your archives are readable only by another account, run as that user
+   instead — the container needs to *list* the archive directory, so `--x`
+   (traverse-only) permissions are not enough:
+   ```bash
+   docker run --user $(stat -c '%u:%g' /path/to/archives) ...
+   ```
+   In Compose:
+   ```yaml
+   services:
+     instaarchive:
+       user: "1234:1234"   # a UID that can read your archives
+   ```
+
+### Archive Index
+
+On first start the server walks the archive root once and caches the result,
+keyed by directory mtime. This matters on network storage: for a 110k-file
+archive root, listing went from ~52s per request to ~0.1s. Mount a volume at
+`/cache` (or set `CACHE_DIR`) so the index survives restarts, otherwise it is
+rebuilt on every start.
 
 ## Supported Archive Structure
 
@@ -66,5 +98,6 @@ archives/
 **Prerequisites:** Node.js (LTS recommended)
 
 1. **Install dependencies:** `npm install`
-2. **Start dev server:** `npm run dev`
+2. **Start dev server:** `npm run dev` (Frontend on port 3000)
-3. **Start local backend:** `npm run server` (Optional, serves `./_sample-archives`)
+3. **Start local backend:** `npm run server` (Optional, serves `./_sample-archives` on port 3001)
+4. **Build production:** `npm run build` (Generates `./dist` for frontend and `./dist-server` for the API)

compose.yml

@@ -1,12 +1,17 @@
 services:
   instaarchive:
-    image: ghcr.io/${GITHUB_REPOSITORY:-ergosteur/instaarchive-viewer}:latest
+    image: ghcr.io/ergosteur/instaarchive-viewer:latest
-    build: .
     ports:
       - "3000:3000"
     volumes:
-      - ./archives:/archives:ro
+      - ./archives:/archives:ro,z
+      # Persists the archive index so restarts don't re-walk every file.
+      - instaarchive-cache:/cache
     environment:
       - PORT=3000
       - ARCHIVES_DIR=/archives
+      - CACHE_DIR=/cache
     restart: unless-stopped
+
+volumes:
+  instaarchive-cache:

package.json

@@ -1,7 +1,7 @@
 {
-  "name": "react-example",
+  "name": "instaarchive-viewer",
   "private": true,
-  "version": "1.1.1",
+  "version": "1.7.0",
   "type": "module",
   "scripts": {
     "dev": "vite --port=3000 --host=0.0.0.0",
@@ -10,13 +10,14 @@
     "preview": "vite preview",
     "server": "tsx server.ts",
     "clean": "rm -rf dist",
-    "lint": "tsc --noEmit"
+    "lint": "tsc --noEmit",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "jd2": "tsx scripts/jd2-sync.ts"
   },
   "dependencies": {
-    "@google/genai": "^1.29.0",
     "@tailwindcss/vite": "^4.1.14",
     "@vitejs/plugin-react": "^5.0.4",
-    "better-sqlite3": "^12.4.1",
     "clsx": "^2.1.1",
     "date-fns": "^4.1.0",
     "dotenv": "^17.2.3",
@@ -34,10 +35,13 @@
   "devDependencies": {
     "@types/express": "^4.17.21",
     "@types/node": "^22.14.0",
+    "@types/react": "^19.2.18",
+    "@types/react-dom": "^19.2.4",
     "autoprefixer": "^10.4.21",
     "tailwindcss": "^4.1.14",
     "typescript": "~5.8.2",
     "vite": "^6.2.0",
-    "vite-plugin-pwa": "^1.2.0"
+    "vite-plugin-pwa": "^1.2.0",
+    "vitest": "^3.2.7"
   }
 }

public/fonts/fonts.css

@@ -0,0 +1,56 @@
+/* Self-hosted subset of Inter + Playfair Display.
+   Vendored so the PWA works offline and makes no third-party requests. */
+/* latin-ext */
+@font-face {
+  font-family: 'Inter';
+  font-style: normal;
+  font-weight: 300 700;
+  font-display: swap;
+  src: url(/fonts/inter-300_700-normal-b6db4a.woff2) format('woff2');
+  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
+}
+/* latin */
+@font-face {
+  font-family: 'Inter';
+  font-style: normal;
+  font-weight: 300 700;
+  font-display: swap;
+  src: url(/fonts/inter-300_700-normal-6ab57b.woff2) format('woff2');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
+}
+/* latin-ext */
+@font-face {
+  font-family: 'Playfair Display';
+  font-style: italic;
+  font-weight: 400 900;
+  font-display: swap;
+  src: url(/fonts/playfair-display-400_900-italic-2d6d99.woff2) format('woff2');
+  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
+}
+/* latin */
+@font-face {
+  font-family: 'Playfair Display';
+  font-style: italic;
+  font-weight: 400 900;
+  font-display: swap;
+  src: url(/fonts/playfair-display-400_900-italic-d14361.woff2) format('woff2');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
+}
+/* latin-ext */
+@font-face {
+  font-family: 'Playfair Display';
+  font-style: normal;
+  font-weight: 400 900;
+  font-display: swap;
+  src: url(/fonts/playfair-display-400_900-normal-ca7410.woff2) format('woff2');
+  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+0304, U+0308, U+0329, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
+}
+/* latin */
+@font-face {
+  font-family: 'Playfair Display';
+  font-style: normal;
+  font-weight: 400 900;
+  font-display: swap;
+  src: url(/fonts/playfair-display-400_900-normal-61a963.woff2) format('woff2');
+  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
+}

server.ts

@@ -3,6 +3,8 @@ import fs from 'fs';
 import path from 'path';
 import { fileURLToPath } from 'url';
 import dotenv from 'dotenv';
+import os from 'os';
+import { ArchiveIndex } from './src/lib/archive-index.js';
 
 dotenv.config();
 
@@ -14,90 +16,155 @@ const PORT = process.env.PORT || 3001;
 const ARCHIVES_DIR = path.resolve(process.env.ARCHIVES_DIR || path.join(__dirname, '_sample-archives'));
 
 console.log(`[Server] Initializing...`);
+/**
+ * Describe the running user without assuming it exists in /etc/passwd.
+ *
+ * `os.userInfo()` throws ENOENT for a UID with no passwd entry, which is
+ * exactly what happens when the container is started with `--user 1234:1234`
+ * (as the deployment docs suggest) — previously crashing the server at boot.
+ */
+const describeUser = () => {
+  try {
+    const info = os.userInfo();
+    return `${info.username} (UID: ${info.uid}, GID: ${info.gid})`;
+  } catch {
+    return `UID: ${typeof process.getuid === 'function' ? process.getuid() : '?'}, GID: ${typeof process.getgid === 'function' ? process.getgid() : '?'} (no passwd entry)`;
+  }
+};
+
+console.log(`[Server] Running as user: ${describeUser()}`);
 console.log(`[Server] Environment ARCHIVES_DIR: ${process.env.ARCHIVES_DIR}`);
 console.log(`[Server] Resolved ARCHIVES_DIR: ${ARCHIVES_DIR}`);
 
 // Ensure archives directory exists
 if (!fs.existsSync(ARCHIVES_DIR)) {
   console.warn(`[Server] Warning: Archives directory not found at ${ARCHIVES_DIR}. Creating it...`);
-  fs.mkdirSync(ARCHIVES_DIR, { recursive: true });
+  try {
+    fs.mkdirSync(ARCHIVES_DIR, { recursive: true });
+  } catch (err) {
+    console.error(`[Server] Failed to create archives directory:`, err);
+  }
 } else {
   console.log(`[Server] Archives directory exists.`);
 }
 
+const INDEX_PATH = process.env.ARCHIVE_INDEX_PATH
+  || path.join(process.env.CACHE_DIR || os.tmpdir(), 'instaarchive-index.json');
+const index = new ArchiveIndex(ARCHIVES_DIR, INDEX_PATH);
+
+// Warm in the background: the first walk of a large archive root is slow, but
+// everything after it is served from directory-mtime-keyed cache.
+index.load()
+  .then(() => index.warm())
+  .catch(err => console.error('[Index] Warm failed:', err));
+
+// Don't advertise the framework.
+app.disable('x-powered-by');
+
+/**
+ * Baseline security headers.
+ *
+ * The CSP allows blob: and data: because archive media is rendered from object
+ * URLs and cached thumbnails, and 'unsafe-inline' for styles because the
+ * animation library sets inline styles. Scripts stay restricted to same-origin,
+ * and no third-party origins are permitted at all — the app bundles its own
+ * fonts and icons.
+ */
+app.use((req, res, next) => {
+  res.setHeader('X-Content-Type-Options', 'nosniff');
+  res.setHeader('X-Frame-Options', 'SAMEORIGIN');
+  res.setHeader('Referrer-Policy', 'no-referrer');
+  res.setHeader('Cross-Origin-Resource-Policy', 'same-origin');
+  res.setHeader('Permissions-Policy', 'geolocation=(), microphone=(), camera=(), interest-cohort=()');
+  res.setHeader('Content-Security-Policy', [
+    "default-src 'self'",
+    "img-src 'self' blob: data:",
+    "media-src 'self' blob: data:",
+    // 'wasm-unsafe-eval' permits WebAssembly compilation without allowing
+    // eval() of JavaScript. The xz decompressor used for Instaloader's
+    // .json.xz sidecars is WebAssembly, embedded as a data: URL it fetches at
+    // startup — so connect-src must allow data: too. Without both, decoding
+    // fails with a bare "TypeError: Failed to fetch" and every archive silently
+    // loses its captions, story flags and profile metadata.
+    "script-src 'self' 'wasm-unsafe-eval'",
+    "style-src 'self' 'unsafe-inline'",
+    "font-src 'self'",
+    "connect-src 'self' data:",
+    "worker-src 'self' blob:",
+    "frame-ancestors 'self'",
+    "object-src 'none'",
+    "base-uri 'self'",
+    "form-action 'self'",
+  ].join('; '));
+  next();
+});
+
 app.use(express.json());
 
-// API: List archives (subdirectories in ARCHIVES_DIR)
+/**
+ * Resolve a user-supplied archive name to an absolute path inside ARCHIVES_DIR.
+ *
+ * Express decodes route params *after* segment matching, so a name like
+ * `..%2f..%2fetc` arrives here as `../../etc` and would otherwise escape the
+ * archives root. Returns null for anything that resolves outside it.
+ */
+const resolveArchivePath = (archiveName: string): string | null => {
+  if (!archiveName || archiveName.includes('\0')) return null;
+  const resolved = path.resolve(ARCHIVES_DIR, archiveName);
+  if (resolved !== ARCHIVES_DIR && !resolved.startsWith(ARCHIVES_DIR + path.sep)) {
+    console.warn(`[Security] Rejected archive name escaping ARCHIVES_DIR: ${archiveName}`);
+    return null;
+  }
+  return resolved;
+};
+
+// API: List archives, grouped by profile. Costs one stat per source directory.
 app.get('/api/archives', (req, res) => {
   try {
-    console.log(`[API] Listing archives from ${ARCHIVES_DIR}...`);
+    const groups = index.groups();
-    const items = fs.readdirSync(ARCHIVES_DIR, { withFileTypes: true });
+    const archives = Array.from(groups.entries()).map(([owner, sources]) => ({
-    console.log(`[API] Found ${items.length} total items in archives directory.`);
+      name: owner,
-    
+      thumbnail: index.thumbnailFor(owner, sources),
-    const archives = items
+      path: owner,
-      .filter(item => {
+      // Null until that profile has been indexed; the client treats it as unknown.
-        const isDir = item.isDirectory();
+      fileCount: index.countFor(sources),
-        if (!isDir) console.log(`[API] Skipping non-directory: ${item.name}`);
+      // Directory mtimes: cheap to compute and enough to invalidate a stale cache.
-        return isDir;
+      signature: index.signatureFor(sources),
-      })
+      sources,
-      .map(item => {
+    }));
-        // Try to find a profile pic or first image for the thumbnail
+    console.log(`[API] Returning ${archives.length} archives.`);
-        const archivePath = path.join(ARCHIVES_DIR, item.name);
-        const files = fs.readdirSync(archivePath);
-        console.log(`[API] Found archive: ${item.name} (${files.length} files)`);
-        
-        let thumbnail = '';
-        const profilePic = files.find(f => f.toLowerCase().includes('_profile_pic.jpg') || f.toLowerCase() === `${item.name.toLowerCase()}.jpg`);
-        if (profilePic) {
-          thumbnail = `/archives/${item.name}/${profilePic}`;
-        } else {
-          const firstImage = files.find(f => /\.(jpg|jpeg|png|webp)$/i.test(f));
-          if (firstImage) thumbnail = `/archives/${item.name}/${firstImage}`;
-        }
-
-        return {
-          name: item.name,
-          thumbnail,
-          path: item.name,
-          fileCount: files.length
-        };
-      });
-    
-    console.log(`[API] Returning ${archives.length} validated archives.`);
     res.json(archives);
-  } catch (err) {
+  } catch (err: any) {
-    console.error('[API] Error listing archives:', err);
+    if (err.code === 'EACCES') {
-    res.status(500).json({ error: 'Failed to list archives' });
+      console.error(`[API] Permission Denied! The server (${describeUser()}) cannot read ${ARCHIVES_DIR}.`);
+      console.error(`[API] Hint: If using Linux/Docker, check folder permissions (chmod 755) or SELinux context (append :z to your volume mount).`);
+    } else {
+      console.error('[API] Error listing archives:', err);
+    }
+    res.status(500).json({ error: 'Permission denied or failed to list archives' });
   }
 });
 
-// API: List all files in an archive (recursive)
+/**
-app.get('/api/archives/:name/files', (req, res) => {
+ * List every file belonging to a profile, across its base and sidecar dirs.
+ *
+ * Paths are relative to ARCHIVES_DIR (so they include the source directory) and
+ * each entry carries its source kind, letting the client route posts, reels,
+ * stories and highlights without re-deriving the naming rules.
+ *
+ * Served from the directory index; only a directory whose mtime changed is
+ * re-walked.
+ */
+app.get('/api/archives/:name/files', async (req, res) => {
   const archiveName = req.params.name;
-  const archivePath = path.join(ARCHIVES_DIR, archiveName);
+  if (!resolveArchivePath(archiveName)) {
-
+    return res.status(400).json({ error: 'Invalid archive name' });
-  if (!fs.existsSync(archivePath)) {
-    return res.status(404).json({ error: 'Archive not found' });
   }
 
   try {
-    const walk = (dir: string, base: string = ''): string[] => {
+    const files = await index.filesFor(archiveName);
-      let results: string[] = [];
+    if (!files) return res.status(404).json({ error: 'Archive not found' });
-      const list = fs.readdirSync(dir);
+    void index.save();
-      list.forEach(file => {
-        const filePath = path.join(dir, file);
-        const relativePath = path.join(base, file);
-        const stat = fs.statSync(filePath);
-        if (stat && stat.isDirectory()) {
-          results = results.concat(walk(filePath, relativePath));
-        } else {
-          results.push(relativePath);
-        }
-      });
-      return results;
-    };
-
-    const files = walk(archivePath);
     res.json(files);
   } catch (err) {
     console.error('Error listing files:', err);
@@ -105,8 +172,14 @@ app.get('/api/archives/:name/files', (req, res) => {
   }
 });
 
-// Serve archive files
+// Serve archive files. Archive contents are immutable in practice, so cache
-app.use('/archives', express.static(ARCHIVES_DIR));
+// them aggressively; the client busts its own cache via fileCount.
+app.use('/archives', express.static(ARCHIVES_DIR, {
+  maxAge: '1y',
+  immutable: true,
+  index: false,
+  dotfiles: 'ignore',
+}));
 
 // Serve production frontend
 const distPath = path.join(__dirname, 'dist');

src/components/ArchiveDashboard.tsx

@@ -0,0 +1,155 @@
+import React from 'react';
+import { 
+  FolderOpen, 
+  Grid3X3, 
+  Play, 
+  Trash2, 
+  Zap 
+} from 'lucide-react';
+import { CacheData, ServerArchive } from '../types';
+
+interface ArchiveDashboardProps {
+  archives: ServerArchive[];
+  localArchives?: CacheData[];
+  cachedArchives: Set<string>;
+  onSelect: (archive: ServerArchive) => void;
+  onLocalSelect: () => void;
+  onLocalCacheSelect: (archive: CacheData) => void;
+  onClearCache: (name: string) => void;
+  isScanning: boolean;
+}
+
+export const ArchiveDashboard: React.FC<ArchiveDashboardProps> = ({ 
+  archives, 
+  localArchives = [],
+  cachedArchives,
+  onSelect,
+  onLocalSelect,
+  onLocalCacheSelect,
+  onClearCache,
+  isScanning
+}) => {
+  return (
+    <div className="max-w-6xl mx-auto px-4 py-12 space-y-12">
+      <div className="text-center space-y-4">
+        <h2 className="text-4xl font-bold tracking-tight font-serif italic text-black/80">Archive Explorer</h2>
+        <p className="text-gray-500 max-w-xl mx-auto text-sm md:text-base leading-relaxed">
+          Browse hosted collections or open a local archive folder. All processing happens locally in your browser for maximum privacy.
+        </p>
+      </div>
+
+      <div className="grid grid-cols-2 md:grid-cols-3 lg:grid-cols-4 gap-4 md:gap-8">
+        {/* Local Folder Card */}
+        <button 
+          onClick={onLocalSelect}
+          disabled={isScanning}
+          className="aspect-[3/4] rounded-xl border-2 border-dashed border-gray-200 hover:border-blue-400 hover:bg-blue-50/50 transition-all flex flex-col items-center justify-center gap-4 group disabled:opacity-50 text-black"
+        >
+          <div className="w-12 h-12 rounded-full bg-gray-100 group-hover:bg-blue-100 flex items-center justify-center text-gray-400 group-hover:text-blue-500 transition-colors shadow-inner">
+            <FolderOpen size={24} />
+          </div>
+          <div className="text-center px-4">
+            <span className="font-bold text-sm block text-black/80">Open Local Folder</span>
+            <span className="text-[10px] text-gray-400 uppercase tracking-widest leading-tight block mt-1">Processed in Browser</span>
+          </div>
+        </button>
+
+        {/* Server Archives */}
+        {archives.map((archive) => {
+          const isCached = cachedArchives.has(archive.name);
+          return (
+            <div key={archive.path} className="relative group text-black">
+              <button
+                onClick={() => onSelect(archive)}
+                disabled={isScanning}
+                className="w-full aspect-[3/4] rounded-xl overflow-hidden bg-white shadow-sm border border-gray-100 hover:shadow-xl hover:scale-[1.02] transition-all flex flex-col text-left disabled:opacity-50"
+              >
+                <div className="flex-1 bg-gray-100 overflow-hidden relative">
+                  {archive.thumbnail ? (
+                    <img src={archive.thumbnail} alt="" className="w-full h-full object-cover" />
+                  ) : (
+                    <div className="w-full h-full flex items-center justify-center text-gray-300">
+                      <Grid3X3 size={48} strokeWidth={1} />
+                    </div>
+                  )}
+                  <div className="absolute inset-0 bg-black/20 opacity-0 hover:opacity-100 transition-opacity flex items-center justify-center">
+                    <Play size={32} fill="white" className="text-white" />
+                  </div>
+                  
+                  {isCached && (
+                    <div className="absolute top-2 left-2 bg-blue-500 text-white p-1 rounded-md shadow-lg flex items-center gap-1 text-[8px] font-bold uppercase tracking-wider z-10 pr-2 opacity-0 group-hover:opacity-100 transition-all">
+                      <Zap size={10} fill="currentColor" />
+                      Cached
+                    </div>
+                  )}
+                </div>
+                <div className="p-4 space-y-1">
+                  <span className="font-bold text-sm block truncate uppercase tracking-tight text-black/80">{archive.name}</span>
+                  <span className="text-[10px] text-gray-400 uppercase tracking-widest">
+                    {archive.fileCount === null
+                      ? `${archive.sources?.length ?? 1} source${(archive.sources?.length ?? 1) === 1 ? '' : 's'}`
+                      : `${archive.fileCount} items`}
+                  </span>
+                </div>
+              </button>
+              
+              {isCached && (
+                <button
+                  onClick={(e) => {
+                    e.stopPropagation();
+                    onClearCache(archive.name);
+                  }}
+                  className="absolute top-2 right-2 p-2 bg-white/90 hover:bg-red-50 hover:text-red-500 text-gray-400 rounded-lg shadow-sm opacity-0 group-hover:opacity-100 transition-all z-20"
+                  title="Clear Cache"
+                >
+                  <Trash2 size={14} />
+                </button>
+              )}
+            </div>
+          );
+        })}
+
+        {/* Local Cached Archives */}
+        {localArchives.map((archive) => (
+          <div key={archive.name} className="relative group text-black">
+            <button
+              onClick={() => onLocalCacheSelect(archive)}
+              disabled={isScanning}
+              className="w-full aspect-[3/4] rounded-xl overflow-hidden bg-white shadow-sm border border-gray-100 hover:shadow-xl hover:scale-[1.02] transition-all flex flex-col text-left disabled:opacity-50"
+            >
+              <div className="flex-1 bg-gray-100 overflow-hidden relative text-black">
+                {archive.profileMetadata.profilePic ? (
+                  <img src={archive.profileMetadata.profilePic} alt="" className="w-full h-full object-cover" />
+                ) : (
+                  <div className="w-full h-full flex items-center justify-center text-gray-300">
+                    <Grid3X3 size={48} strokeWidth={1} />
+                  </div>
+                )}
+                <div className="absolute inset-0 bg-black/20 opacity-0 hover:opacity-100 transition-opacity flex items-center justify-center">
+                  <FolderOpen size={32} fill="white" className="text-white" />
+                </div>
+                <div className="absolute bottom-2 left-2 bg-gray-800/80 text-white px-2 py-0.5 rounded text-[8px] font-bold uppercase tracking-widest backdrop-blur-sm">
+                  Local Cache
+                </div>
+              </div>
+              <div className="p-4 space-y-1 text-black">
+                <span className="font-bold text-sm block truncate uppercase tracking-tight text-black/80">{archive.name}</span>
+                <span className="text-[10px] text-gray-400 uppercase tracking-widest">{archive.fileCount} indexed</span>
+              </div>
+            </button>
+            <button
+              onClick={(e) => {
+                e.stopPropagation();
+                onClearCache(archive.name);
+              }}
+              className="absolute top-2 right-2 p-2 bg-white/90 hover:bg-red-50 hover:text-red-500 text-gray-400 rounded-lg shadow-sm opacity-0 group-hover:opacity-100 transition-all z-20"
+              title="Clear Cache"
+            >
+              <Trash2 size={14} />
+            </button>
+          </div>
+        ))}
+      </div>
+    </div>
+  );
+};

src/components/ErrorBoundary.tsx

@@ -0,0 +1,55 @@
+import React from 'react';
+import { AlertTriangle } from 'lucide-react';
+
+interface Props { children: React.ReactNode }
+interface State { error: Error | null }
+
+/**
+ * Keeps one bad archive item from blanking the whole app.
+ *
+ * Post data is derived from filenames and arbitrary archive JSON, so a single
+ * malformed record used to be able to throw during render and take the entire
+ * tree down with it.
+ */
+export class ErrorBoundary extends React.Component<Props, State> {
+  constructor(props: Props) {
+    super(props);
+    this.state = { error: null };
+  }
+
+  static getDerivedStateFromError(error: Error): State {
+    return { error };
+  }
+
+  componentDidCatch(error: Error, info: React.ErrorInfo) {
+    console.error('[ErrorBoundary] Render failed:', error, info.componentStack);
+  }
+
+  render() {
+    if (!this.state.error) return this.props.children;
+
+    return (
+      <div className="min-h-screen bg-gray-50 flex items-center justify-center p-6">
+        <div className="max-w-md w-full bg-white rounded-2xl shadow-sm border border-gray-100 p-8 space-y-4 text-center">
+          <div className="w-12 h-12 mx-auto rounded-full bg-red-50 text-red-500 flex items-center justify-center">
+            <AlertTriangle size={24} />
+          </div>
+          <h2 className="text-xl font-semibold text-black/80">Something went wrong</h2>
+          <p className="text-sm text-gray-500">
+            This archive could not be rendered. Reloading usually clears it; if it
+            persists, clear the cached copy from the archive explorer.
+          </p>
+          <pre className="text-[11px] text-left text-gray-400 bg-gray-50 rounded-lg p-3 overflow-x-auto">
+            {this.state.error.message}
+          </pre>
+          <button
+            onClick={() => window.location.reload()}
+            className="bg-blue-500 hover:bg-blue-600 text-white px-6 py-2 rounded-lg text-sm font-semibold transition-colors"
+          >
+            Reload
+          </button>
+        </div>
+      </div>
+    );
+  }
+}

src/components/FeedPost.tsx

@@ -0,0 +1,67 @@
+import React from 'react';
+import { Bookmark, Heart, MessageCircle, MoreHorizontal, Send } from 'lucide-react';
+import { Post } from '../types';
+import { formatDateSafe } from '../lib/utils';
+import { MediaCarousel } from './MediaCarousel';
+
+interface FeedPostProps {
+  post: Post;
+  profilePic: string | null;
+  /** Off-screen posts keep their video paused. */
+  paused: boolean;
+}
+
+/**
+ * One post in the mobile feed, laid out like Instagram's: header, media,
+ * action row, then caption.
+ *
+ * Media is capped below full viewport height so the next post always peeks in
+ * at the bottom — that overlap is what tells you the page scrolls rather than
+ * pages.
+ */
+export const FeedPost: React.FC<FeedPostProps> = ({ post, profilePic, paused }) => (
+  <article className="bg-white border-b border-gray-200">
+    <header className="flex items-center justify-between px-3 py-2.5">
+      <div className="flex items-center gap-2.5 min-w-0">
+        <div className="w-8 h-8 rounded-full bg-gradient-to-tr from-yellow-400 to-purple-600 p-0.5 shrink-0">
+          <div className="w-full h-full rounded-full bg-white p-0.5">
+            <div className="w-full h-full rounded-full bg-gray-200 overflow-hidden flex items-center justify-center text-[10px] font-bold uppercase">
+              {profilePic
+                ? <img src={profilePic} alt="" className="w-full h-full object-cover" referrerPolicy="no-referrer" />
+                : <span>{post.username[0]}</span>}
+            </div>
+          </div>
+        </div>
+        <span className="font-semibold text-sm truncate">{post.username}</span>
+      </div>
+      <MoreHorizontal size={20} className="text-gray-500 shrink-0" />
+    </header>
+
+    {/*
+      Taller ceiling than the modal so ordinary portrait media (9:16 reels,
+      4:5 photos) fills the feed width instead of sitting in side bars, while
+      still stopping anything extreme from swallowing the screen.
+    */}
+    <MediaCarousel post={post} paused={paused} heightCap="max-h-[85vh]" fillWidth className="bg-black" />
+
+    <div className="px-3 pt-3 pb-1 flex items-center justify-between">
+      <div className="flex items-center gap-4">
+        <Heart size={24} className="cursor-pointer" />
+        <MessageCircle size={24} className="cursor-pointer" />
+        <Send size={24} className="cursor-pointer" />
+      </div>
+      <Bookmark size={24} className="cursor-pointer" />
+    </div>
+
+    {post.caption && (
+      <div className="px-3 pb-1 text-sm">
+        <span className="font-semibold mr-2">{post.username}</span>
+        <span className="whitespace-pre-wrap">{post.caption}</span>
+      </div>
+    )}
+
+    <div className="px-3 pb-3 pt-1 text-[10px] uppercase tracking-wide text-gray-400">
+      {formatDateSafe(post.date, 'MMMM d, yyyy')}
+    </div>
+  </article>
+);

src/components/MediaCarousel.tsx

@@ -0,0 +1,112 @@
+import React, { useEffect, useState } from 'react';
+import { ChevronLeft, ChevronRight } from 'lucide-react';
+import { motion, AnimatePresence } from 'motion/react';
+import { Post } from '../types';
+import { cn } from '../lib/utils';
+import { NAVIGATE, prefersReducedMotion, withVelocity } from '../lib/motion';
+import { MediaRenderer } from './MediaRenderer';
+
+interface MediaCarouselProps {
+  post: Post;
+  /** Pause video even when this slide is on screen (feed: only one plays). */
+  paused?: boolean;
+  /** Override the media height ceiling (the feed allows taller media). */
+  heightCap?: string;
+  /** Size video to the container width (see MediaRenderer). */
+  fillWidth?: boolean;
+  className?: string;
+}
+
+/**
+ * The horizontal slide strip for one post.
+ *
+ * Shared by the desktop modal and the mobile feed so a carousel behaves the
+ * same in both. Horizontal drag belongs to the carousel and never navigates
+ * between posts — vertical movement is the page's to handle.
+ */
+export const MediaCarousel: React.FC<MediaCarouselProps> = ({ post, paused, heightCap, fillWidth, className }) => {
+  const [index, setIndex] = useState(0);
+  const [slide, setSlide] = useState<{ dir: number; velocity: number }>({ dir: 0, velocity: 0 });
+  const reduceMotion = prefersReducedMotion();
+
+  useEffect(() => setIndex(0), [post.id]);
+
+  const paginate = (dir: number, velocity = 0) => {
+    const next = index + dir;
+    if (next < 0 || next >= post.media.length) return;
+    setSlide({ dir, velocity });
+    setIndex(next);
+  };
+
+  const variants = {
+    enter: (d: number) => ({ x: d > 0 ? '100%' : '-100%', opacity: 1, zIndex: 0 }),
+    center: { x: 0, opacity: 1, zIndex: 1 },
+    exit: (d: number) => ({ x: d < 0 ? '100%' : '-100%', opacity: 1, zIndex: 0 }),
+  };
+  const swipePower = (offset: number, velocity: number) => Math.abs(offset) * velocity;
+  const current = post.media[index];
+
+  return (
+    <div className={cn('relative bg-black flex items-center justify-center group overflow-hidden w-full', className)}>
+      <div className="w-full grid grid-cols-1 grid-rows-1">
+        <AnimatePresence initial={false} custom={slide.dir}>
+          <motion.div
+            key={`${post.id}-${index}`}
+            custom={slide.dir}
+            variants={variants}
+            initial="enter"
+            animate="center"
+            exit="exit"
+            transition={reduceMotion ? { duration: 0 } : withVelocity(slide.velocity, NAVIGATE)}
+            drag={post.media.length > 1 ? 'x' : false}
+            dragDirectionLock
+            dragConstraints={{ left: 0, right: 0 }}
+            dragElastic={0.5}
+            onDragEnd={(e, { offset, velocity }) => {
+              const power = swipePower(offset.x, velocity.x);
+              if (power < -15000) paginate(1, velocity.x);
+              else if (power > 15000) paginate(-1, velocity.x);
+            }}
+            className="col-start-1 row-start-1 w-full flex items-center justify-center relative touch-pan-y"
+          >
+            {current && <MediaRenderer file={current} isFullView paused={paused} heightCap={heightCap} fillWidth={fillWidth} />}
+          </motion.div>
+        </AnimatePresence>
+      </div>
+
+      {post.media.length > 1 && (
+        <>
+          {index > 0 && (
+            <button
+              aria-label="Previous photo"
+              onClick={(e) => { e.stopPropagation(); paginate(-1); }}
+              className="hidden md:block absolute left-4 top-1/2 -translate-y-1/2 bg-white/20 hover:bg-white/40 text-white p-2 rounded-full backdrop-blur-md transition-all opacity-0 group-hover:opacity-100 z-30"
+            >
+              <ChevronLeft size={24} />
+            </button>
+          )}
+          {index < post.media.length - 1 && (
+            <button
+              aria-label="Next photo"
+              onClick={(e) => { e.stopPropagation(); paginate(1); }}
+              className="hidden md:block absolute right-4 top-1/2 -translate-y-1/2 bg-white/20 hover:bg-white/40 text-white p-2 rounded-full backdrop-blur-md transition-all opacity-0 group-hover:opacity-100 z-30"
+            >
+              <ChevronRight size={24} />
+            </button>
+          )}
+          <div className="absolute bottom-4 left-1/2 -translate-x-1/2 flex gap-1.5 z-30">
+            {post.media.map((_, i) => (
+              <div
+                key={i}
+                className={cn(
+                  'w-1.5 h-1.5 rounded-full transition-all',
+                  i === index ? 'bg-blue-500 scale-125' : 'bg-white/40 shadow-sm',
+                )}
+              />
+            ))}
+          </div>
+        </>
+      )}
+    </div>
+  );
+};

src/components/MediaRenderer.tsx

@@ -0,0 +1,84 @@
+import React, { useState, useEffect, useRef } from 'react';
+import { Play, Volume2, VolumeX } from 'lucide-react';
+import { MediaFile } from '../types';
+import { cn } from '../lib/utils';
+
+interface MediaRendererProps {
+  file: MediaFile;
+  className?: string;
+  isFullView?: boolean;
+  /** Hold playback: the feed keeps every off-screen video paused. */
+  paused?: boolean;
+  /** Cap media height to this instead of the default full-view ceiling. */
+  heightCap?: string;
+  /**
+   * Size video to the container width rather than its own intrinsic size.
+   *
+   * A <video> reports 300x150 until metadata loads, so `w-auto` makes it render
+   * narrow and then jump to full width. The feed needs a stable width more than
+   * it needs a snug fit.
+   */
+  fillWidth?: boolean;
+}
+
+export const MediaRenderer = ({ file, className, isFullView, paused, heightCap, fillWidth }: MediaRendererProps) => {
+  // Try to play with sound: opening the modal is a user gesture, so browsers
+  // generally allow it. If this particular browser still refuses, the effect
+  // below falls back to muted playback rather than leaving a stalled video.
+  const [isMuted, setIsMuted] = useState(false);
+  const videoRef = useRef<HTMLVideoElement>(null);
+
+  useEffect(() => {
+    const video = videoRef.current;
+    if (!video || file.type !== 'video') return;
+
+    if (paused) {
+      video.pause();
+      return;
+    }
+
+    let cancelled = false;
+    video.muted = false;
+    video.play().catch(() => {
+      if (cancelled) return;
+      setIsMuted(true);
+      video.muted = true;
+      video.play().catch(() => { /* user can start it from the controls */ });
+    });
+
+    return () => { cancelled = true; };
+  }, [file.url, file.type, paused]);
+  /**
+   * In full view the media must never outgrow the viewport.
+   *
+   * Video is sized to its own aspect within the cap (`w-auto`) so a portrait
+   * clip doesn't sit in a wide letterbox, while images keep filling the modal
+   * width and only gain a height ceiling — `object-contain` stops the cap from
+   * distorting anything that hits it.
+   *
+   * The desktop cap subtracts the modal's own padding (md:p-10 = 2.5rem each
+   * side); mobile leaves room for the caption panel stacked underneath.
+   */
+  const fullViewCap = `${heightCap ?? 'max-h-[70vh] md:max-h-[calc(100vh-5rem)]'} object-contain`;
+  const videoFullView = fillWidth
+    ? `block w-full h-auto ${fullViewCap}`
+    : `block w-auto max-w-full ${fullViewCap}`;
+  const videoSizing = isFullView ? videoFullView : "w-full h-full object-cover";
+  const imageSizing = isFullView ? `block w-full h-auto ${fullViewCap}` : "w-full h-full object-cover";
+  const sizingClass = file.type === 'video' ? videoSizing : imageSizing;
+  const mediaStyle = { transform: 'translateZ(0)' };
+
+  if (!file.url) return <div className={cn("bg-gray-100 flex items-center justify-center text-black", sizingClass)}><Play size={24} className="text-gray-300" /></div>;
+
+  if (file.type === 'video') {
+    return (
+      <div className="relative w-full h-full flex items-center justify-center group/video text-black">
+        <video ref={videoRef} src={file.url} className={cn("transition-all duration-300", sizingClass, className)} style={mediaStyle} playsInline autoPlay muted={isMuted} loop controls />
+        <button onClick={(e) => { e.stopPropagation(); setIsMuted(!isMuted); }} className="absolute bottom-16 right-4 z-30 bg-black/40 hover:bg-black/60 text-white p-2 rounded-full backdrop-blur-md transition-all md:opacity-0 md:group-hover/video:opacity-100">
+          {isMuted ? <VolumeX size={20} /> : <Volume2 size={20} />}
+        </button>
+      </div>
+    );
+  }
+  return <img src={file.url} alt="" className={cn("transition-all duration-300", sizingClass, className)} style={mediaStyle} referrerPolicy="no-referrer" decoding="async" loading="eager" />;
+};

src/components/PostFeed.tsx

@@ -0,0 +1,150 @@
+import React, { useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } from 'react';
+import { ChevronLeft } from 'lucide-react';
+import { Post } from '../types';
+import { FeedPost } from './FeedPost';
+
+interface PostFeedProps {
+  posts: Post[];
+  /** Post the feed should open at. */
+  initialPostId: string;
+  profilePic: string | null;
+  onClose: () => void;
+  /** Fires as the post crossing the viewport centre changes. */
+  onActivePostChange: (post: Post) => void;
+  title?: string;
+}
+
+/** Posts added each time the feed grows in either direction. */
+const BATCH = 6;
+/** Render this many ahead of the entry point so the first scroll is smooth. */
+const LOOKAHEAD = 3;
+
+/**
+ * The mobile post view: a real scrolling feed, not a modal.
+ *
+ * Only a window of posts around the entry point is mounted — a profile can hold
+ * thousands, and mounting them all would mean thousands of full-size images.
+ * The window grows in both directions as you scroll; growing *upwards* shifts
+ * everything below it, so the scroll position is corrected in the same frame to
+ * keep the content under your thumb still.
+ */
+export const PostFeed: React.FC<PostFeedProps> = ({
+  posts, initialPostId, profilePic, onClose, onActivePostChange, title,
+}) => {
+  const initialIndex = useMemo(() => {
+    const found = posts.findIndex(p => p.id === initialPostId);
+    return found === -1 ? 0 : found;
+  }, [posts, initialPostId]);
+
+  const [range, setRange] = useState(() => ({
+    start: initialIndex,
+    end: Math.min(posts.length, initialIndex + LOOKAHEAD + 1),
+  }));
+  const [activeId, setActiveId] = useState(initialPostId);
+
+  const scrollRef = useRef<HTMLDivElement>(null);
+  const topSentinelRef = useRef<HTMLDivElement>(null);
+  const bottomSentinelRef = useRef<HTMLDivElement>(null);
+  /** Distance from the bottom of the content, captured before a prepend. */
+  const anchorRef = useRef<number | null>(null);
+
+  const visible = posts.slice(range.start, range.end);
+
+  const extendDown = useCallback(() => {
+    setRange(r => (r.end >= posts.length ? r : { ...r, end: Math.min(posts.length, r.end + BATCH) }));
+  }, [posts.length]);
+
+  const extendUp = useCallback(() => {
+    const el = scrollRef.current;
+    if (!el) return;
+    setRange(r => {
+      if (r.start === 0) return r;
+      // Measure from the bottom: prepending changes scrollHeight, but the
+      // distance between our position and the end of the content does not.
+      anchorRef.current = el.scrollHeight - el.scrollTop;
+      return { ...r, start: Math.max(0, r.start - BATCH) };
+    });
+  }, []);
+
+  // Restore the scroll position in the same frame the prepended posts appear,
+  // before the browser paints, so nothing visibly jumps.
+  useLayoutEffect(() => {
+    const el = scrollRef.current;
+    if (el && anchorRef.current !== null) {
+      el.scrollTop = el.scrollHeight - anchorRef.current;
+      anchorRef.current = null;
+    }
+  }, [range.start]);
+
+  // Grow the window when either end comes into view.
+  useEffect(() => {
+    const root = scrollRef.current;
+    if (!root) return;
+    const observer = new IntersectionObserver(entries => {
+      for (const entry of entries) {
+        if (!entry.isIntersecting) continue;
+        if (entry.target === bottomSentinelRef.current) extendDown();
+        if (entry.target === topSentinelRef.current) extendUp();
+      }
+    }, { root, rootMargin: '600px 0px' });
+
+    if (topSentinelRef.current) observer.observe(topSentinelRef.current);
+    if (bottomSentinelRef.current) observer.observe(bottomSentinelRef.current);
+    return () => observer.disconnect();
+  }, [extendDown, extendUp]);
+
+  // Track the post crossing the viewport centre. The negative margins collapse
+  // the root to a thin band, so exactly one post qualifies at a time.
+  useEffect(() => {
+    const root = scrollRef.current;
+    if (!root) return;
+    const observer = new IntersectionObserver(entries => {
+      for (const entry of entries) {
+        if (!entry.isIntersecting) continue;
+        const id = (entry.target as HTMLElement).dataset.postId;
+        if (id) setActiveId(id);
+      }
+    }, { root, rootMargin: '-45% 0px -45% 0px', threshold: 0 });
+
+    root.querySelectorAll('[data-post-id]').forEach(el => observer.observe(el));
+    return () => observer.disconnect();
+  }, [visible.length, range.start]);
+
+  useEffect(() => {
+    const post = posts.find(p => p.id === activeId);
+    if (post) onActivePostChange(post);
+  }, [activeId, posts, onActivePostChange]);
+
+  // Escape closes, matching the modal it replaces.
+  useEffect(() => {
+    const onKey = (e: KeyboardEvent) => { if (e.key === 'Escape') onClose(); };
+    window.addEventListener('keydown', onKey);
+    return () => window.removeEventListener('keydown', onKey);
+  }, [onClose]);
+
+  return (
+    <div className="fixed inset-0 z-50 bg-white flex flex-col">
+      <header className="flex items-center gap-3 px-2 h-12 border-b border-gray-200 bg-white/95 backdrop-blur-md shrink-0">
+        <button onClick={onClose} aria-label="Back" className="p-2 -ml-1 active:opacity-60">
+          <ChevronLeft size={24} />
+        </button>
+        <span className="font-semibold text-base">{title ?? 'Posts'}</span>
+      </header>
+
+      <div ref={scrollRef} className="flex-1 overflow-y-auto overscroll-contain">
+        <div ref={topSentinelRef} aria-hidden />
+        {visible.map(post => (
+          <div key={post.id} data-post-id={post.id}>
+            <FeedPost post={post} profilePic={profilePic} paused={post.id !== activeId} />
+          </div>
+        ))}
+        <div ref={bottomSentinelRef} aria-hidden />
+        {range.end >= posts.length && (
+          <div className="py-10 text-center text-xs uppercase tracking-widest text-gray-400">
+            End of {title?.toLowerCase() ?? 'posts'}
+          </div>
+        )}
+      </div>
+    </div>
+  );
+};

src/components/PostModal.tsx

@@ -0,0 +1,219 @@
+import React, { useState, useEffect } from 'react';
+import { 
+  ChevronLeft, 
+  ChevronRight, 
+  X, 
+  MoreHorizontal, 
+  Heart, 
+  MessageCircle, 
+  Play, 
+  Bookmark 
+} from 'lucide-react';
+import { motion, AnimatePresence } from 'motion/react';
+import { Post } from '../types';
+import { cn, formatDateSafe } from '../lib/utils';
+import { FADE, NAVIGATE, PRESENT, prefersReducedMotion, withVelocity } from '../lib/motion';
+import { MediaRenderer } from './MediaRenderer';
+
+interface PostModalProps {
+  post: Post;
+  nextPost?: Post;
+  prevPost?: Post;
+  onClose: () => void;
+  onNextPost?: () => void;
+  onPrevPost?: () => void;
+  hasNextPost?: boolean;
+  hasPrevPost?: boolean;
+  profilePic: string | null;
+}
+
+export const PostModal: React.FC<PostModalProps> = ({ 
+  post, nextPost, prevPost, onClose, onNextPost, onPrevPost, hasNextPost, hasPrevPost, profilePic
+}) => {
+  const [currentIndex, setCurrentIndex] = useState(0);
+  /**
+   * How the next slide/post should enter: along which axis, in which direction,
+   * and carrying how much velocity from the gesture that triggered it.
+   */
+  const [slideMotion, setSlideMotion] = useState<{ axis: 'x' | 'y'; dir: number; velocity: number }>(
+    { axis: 'x', dir: 0, velocity: 0 },
+  );
+  const reduceMotion = prefersReducedMotion();
+
+  // Preloading Logic
+  useEffect(() => {
+    const controller = new AbortController();
+    
+    const preloadMedia = async (url: string, type: 'image' | 'video') => {
+      if (!url) return;
+      try {
+        if (type === 'image') {
+          const img = new Image();
+          img.src = url;
+        } else {
+          const video = document.createElement('video');
+          video.src = url;
+          video.preload = 'auto';
+        }
+      } catch (e) {}
+    };
+
+    // 1. Current post: Immediate preload of first two slides
+    if (post.media[0]) preloadMedia(post.media[0].url, post.media[0].type);
+    if (post.media[1]) preloadMedia(post.media[1].url, post.media[1].type);
+
+    // 2. Next/Prev posts: Preload their first slides
+    if (nextPost?.media[0]) preloadMedia(nextPost.media[0].url, nextPost.media[0].type);
+    if (prevPost?.media[0]) preloadMedia(prevPost.media[0].url, prevPost.media[0].type);
+
+    // 3. Current post: Delayed preload of the rest
+    const timeout = setTimeout(() => {
+      for (let i = 2; i < post.media.length; i++) {
+        if (controller.signal.aborted) break;
+        preloadMedia(post.media[i].url, post.media[i].type);
+      }
+    }, 1000);
+
+    return () => {
+      controller.abort();
+      clearTimeout(timeout);
+    };
+  }, [post.id, post.media, nextPost?.id, prevPost?.id]);
+
+  useEffect(() => setCurrentIndex(0), [post.id]);
+  useEffect(() => {
+    // Arrows page within the carousel — the thing the arrows visually point at.
+    // Moving between posts stays on the side buttons, with , and . as keyboard
+    // equivalents.
+    const handleKeyDown = (e: KeyboardEvent) => {
+      if (e.key === 'ArrowRight') paginate(1);
+      else if (e.key === 'ArrowLeft') paginate(-1);
+      else if (e.key === '.') goToPost(1, 'x');
+      else if (e.key === ',') goToPost(-1, 'x');
+      else if (e.key === 'Escape') onClose();
+    };
+    window.addEventListener('keydown', handleKeyDown);
+    return () => window.removeEventListener('keydown', handleKeyDown);
+  }, [onNextPost, onPrevPost, currentIndex, post.media.length, onClose]);
+
+  const paginate = (newDirection: number, velocity = 0) => {
+    const nextIndex = currentIndex + newDirection;
+    if (nextIndex >= 0 && nextIndex < post.media.length) {
+      setSlideMotion({ axis: 'x', dir: newDirection, velocity });
+      setCurrentIndex(nextIndex);
+    }
+  };
+
+  /**
+   * Move between posts, animating along the axis the input implies: vertical
+   * for a touch swipe, horizontal for the desktop arrows and arrow keys.
+   */
+  const goToPost = (dir: 1 | -1, axis: 'x' | 'y', velocity = 0) => {
+    if (dir > 0 ? !hasNextPost : !hasPrevPost) return;
+    setSlideMotion({ axis, dir, velocity });
+    if (dir > 0) onNextPost?.(); else onPrevPost?.();
+  };
+
+  type SlideMotion = { axis: 'x' | 'y'; dir: number };
+  const offscreen = (dir: number) => (dir > 0 ? '100%' : '-100%');
+  const variants = {
+    enter: ({ axis, dir }: SlideMotion) =>
+      axis === 'y'
+        ? { y: offscreen(dir), x: 0, opacity: 1, zIndex: 0 }
+        : { x: offscreen(dir), y: 0, opacity: 1, zIndex: 0 },
+    center: { zIndex: 1, x: 0, y: 0, opacity: 1 },
+    exit: ({ axis, dir }: SlideMotion) =>
+      axis === 'y'
+        ? { zIndex: 0, y: offscreen(-dir), x: 0, opacity: 1 }
+        : { zIndex: 0, x: offscreen(-dir), y: 0, opacity: 1 },
+  };
+  const swipePower = (offset: number, velocity: number) => Math.abs(offset) * velocity;
+
+  /**
+   * Desktop-only surface: mobile opens PostFeed instead, so the only vertical
+   * gesture left here is drag-to-dismiss.
+   */
+  const handleVerticalDragEnd = (offset: { y: number }, velocity: { y: number }) => {
+    if (offset.y > 200 || velocity.y > 800) onClose();
+  };
+
+  /*
+   * Horizontal padding on the overlay reserves a gutter for the prev/next
+   * arrows so they always sit *outside* the modal. Without it the modal grows
+   * until it sits under them and a white chevron lands on the white caption
+   * panel, leaving the control invisible until hovered.
+   *
+   * overscroll-contain stops wheel events chaining through to the very long
+   * post grid behind the overlay.
+   */
+  return (
+    <motion.div initial={{ opacity: 0 }} animate={{ opacity: 1 }} exit={{ opacity: 0 }} transition={FADE} className="fixed inset-0 z-50 flex items-start justify-center bg-[#0c1014]/95 md:bg-[#0c1014]/70 p-0 md:py-10 md:px-16 lg:px-24 overflow-y-auto overscroll-contain text-black" onClick={onClose}>
+      <div className="min-h-full w-full flex items-center justify-center md:py-0">
+        <button onClick={onClose} className="fixed top-4 right-4 text-white hover:text-gray-300 z-50 p-2 md:p-3 bg-black/20 rounded-full backdrop-blur-sm"><X size={24} className="md:w-8 md:h-8" /></button>
+        {/* Solid pill so the arrows read against whatever sits behind them. */}
+        {hasPrevPost && onPrevPost && <button aria-label="Previous post" onClick={(e) => { e.stopPropagation(); goToPost(-1, 'x'); }} className="hidden md:flex items-center justify-center fixed md:left-3 lg:left-6 top-1/2 -translate-y-1/2 z-50 p-2 rounded-full bg-white/90 hover:bg-white text-gray-800 shadow-lg transition-transform hover:scale-110 active:scale-90"><ChevronLeft size={28} strokeWidth={2} /></button>}
+        {hasNextPost && onNextPost && <button aria-label="Next post" onClick={(e) => { e.stopPropagation(); goToPost(1, 'x'); }} className="hidden md:flex items-center justify-center fixed md:right-3 lg:right-6 top-1/2 -translate-y-1/2 z-50 p-2 rounded-full bg-white/90 hover:bg-white text-gray-800 shadow-lg transition-transform hover:scale-110 active:scale-90"><ChevronRight size={28} strokeWidth={2} /></button>}
+        <motion.div drag="y" dragDirectionLock dragConstraints={{ top: 0, bottom: 0 }} dragElastic={0.15} onDragEnd={(e, { offset, velocity }) => handleVerticalDragEnd(offset, velocity)} initial={reduceMotion ? false : { opacity: 0, scale: 0.96 }} animate={{ opacity: 1, scale: 1 }} exit={reduceMotion ? { opacity: 0 } : { opacity: 0, scale: 0.96 }} transition={PRESENT} className="bg-black flex flex-col md:flex-row w-full max-w-6xl h-auto md:rounded-sm overflow-hidden shadow-2xl relative text-black" onClick={e => e.stopPropagation()}>
+          <div className="relative bg-black flex items-center justify-center group overflow-hidden w-full h-auto text-black">
+            <div className="w-full grid grid-cols-1 grid-rows-1 text-black">
+              <AnimatePresence initial={false} custom={slideMotion}>
+                <motion.div
+                  key={`${post.id}-${currentIndex}`}
+                  custom={slideMotion}
+                  variants={variants}
+                  initial="enter"
+                  animate="center"
+                  exit="exit"
+                  transition={reduceMotion
+                    ? { duration: 0 }
+                    : { x: withVelocity(slideMotion.velocity, NAVIGATE), y: withVelocity(slideMotion.velocity, NAVIGATE) }}
+                  
+                  drag="x" 
+                  dragDirectionLock 
+                  dragConstraints={{ left: 0, right: 0 }} 
+                  dragElastic={0.5} 
+                  onDragEnd={(e, { offset, velocity }) => {
+                    // Carousel only. Crossing into the next post from the last
+                    // slide made a horizontal flick mean two different things.
+                    const s = swipePower(offset.x, velocity.x);
+                    if (s < -15000) paginate(1, velocity.x);
+                    else if (s > 15000) paginate(-1, velocity.x);
+                  }} 
+                  className="col-start-1 row-start-1 w-full flex items-center justify-center cursor-grab active:cursor-grabbing relative text-black"
+                >
+                  <MediaRenderer file={post.media[currentIndex]} isFullView={true} />
+                </motion.div>
+              </AnimatePresence>
+            </div>
+            {post.media.length > 1 && (
+              <>
+                {currentIndex > 0 && <button onClick={(e) => { e.stopPropagation(); paginate(-1); }} className="hidden md:block absolute left-4 top-1/2 -translate-y-1/2 bg-white/20 hover:bg-white/40 text-white p-2 rounded-full backdrop-blur-md transition-all opacity-0 group-hover:opacity-100 z-30"><ChevronLeft size={24} /></button>}
+                {currentIndex < post.media.length - 1 && <button onClick={(e) => { e.stopPropagation(); paginate(1); }} className="hidden md:block absolute right-4 top-1/2 -translate-y-1/2 bg-white/20 hover:bg-white/40 text-white p-2 rounded-full backdrop-blur-md transition-all opacity-0 group-hover:opacity-100 z-30"><ChevronRight size={24} /></button>}
+                <div className="absolute bottom-4 left-1/2 -translate-x-1/2 flex gap-1.5 z-30 text-black">{post.media.map((_, i) => <div key={i} className={cn("w-1.5 h-1.5 rounded-full transition-all", i === currentIndex ? "bg-blue-500 scale-125" : "bg-white/40 shadow-sm")} />)}</div>
+              </>
+            )}
+          </div>
+          <div className="w-full md:w-80 lg:w-96 bg-white flex flex-col border-l border-gray-200 overflow-hidden shrink-0 text-black">
+            <div className="p-3 md:p-4 border-b border-gray-100 flex items-center justify-between shrink-0 text-black">
+              <div className="flex items-center gap-3 text-black">
+                <div className="w-8 h-8 rounded-full bg-gradient-to-tr from-yellow-400 to-purple-600 p-0.5 text-black"><div className="w-full h-full rounded-full bg-white p-0.5 text-black"><div className="w-full h-full rounded-full bg-gray-200 flex items-center justify-center overflow-hidden text-[10px] font-bold uppercase text-black">{profilePic ? <img src={profilePic} alt="" className="w-full h-full object-cover text-black" referrerPolicy="no-referrer" /> : <span className="text-black">{post.username[0]}</span>}</div></div></div>
+                <span className="font-semibold text-sm text-black">{post.username}</span>
+              </div>
+              <MoreHorizontal size={20} className="text-gray-500 text-black" />
+            </div>
+            <div className="flex-1 overflow-y-auto p-3 md:p-4 space-y-4 min-h-0 md:max-h-[60vh] text-black">
+              <div className="flex gap-3 text-black">
+                <div className="w-8 h-8 rounded-full bg-gray-200 flex-shrink-0 flex items-center justify-center text-[10px] font-bold uppercase overflow-hidden text-black">{profilePic ? <img src={profilePic} alt="" className="w-full h-full object-cover" referrerPolicy="no-referrer" /> : <span className="text-black">{post.username[0]}</span>}</div>
+                <div className="text-sm text-black"><span className="font-semibold mr-2 text-black">{post.username}</span><span className="whitespace-pre-wrap text-black">{post.caption}</span><div className="mt-2 text-xs text-gray-500 uppercase tracking-tight text-black">{formatDateSafe(post.date, 'MMMM d, yyyy')}</div></div>
+              </div>
+            </div>
+            <div className="p-3 md:p-4 border-t border-gray-100 space-y-3 shrink-0 bg-white text-black">
+              <div className="flex items-center justify-between text-black"><div className="flex items-center gap-4 text-black"><Heart size={24} className="hover:text-gray-500 cursor-pointer text-black" /><MessageCircle size={24} className="hover:text-gray-500 cursor-pointer text-black" /><Play size={24} className="hover:text-gray-500 cursor-pointer text-black" /></div><Bookmark size={24} className="hover:text-gray-500 cursor-pointer text-black" /></div>
+              <div className="text-sm flex items-center gap-2 text-black"><span className="font-semibold text-black">Archived Post</span><span className="text-gray-400 font-normal text-xs text-black">{post.id}</span></div>
+            </div>
+          </div>
+        </motion.div>
+      </div>
+    </motion.div>
+  );
+};

src/components/PostThumbnail.tsx

@@ -0,0 +1,124 @@
+import React, { useState, useEffect, useRef } from 'react';
+import { Play, Image as ImageIcon } from 'lucide-react';
+import { cn } from '../lib/utils';
+import { Post } from '../types';
+
+interface PostThumbnailProps {
+  post: Post;
+  className?: string;
+  thumbnailUrl?: string; // High-res thumbnail from queue
+  onRequestThumbnail: (id: string, url: string) => void;
+}
+
+const videoThumbnailCache = new Map<string, string>();
+
+export const PostThumbnail = ({ post, className, thumbnailUrl, onRequestThumbnail }: PostThumbnailProps) => {
+  const [videoThumbnail, setVideoThumbnail] = useState<string | null>(videoThumbnailCache.get(post.media[0].url) || null);
+  const [isInView, setIsInView] = useState(false);
+  const containerRef = useRef<HTMLDivElement>(null);
+
+  const mainMedia = post.media[0];
+  const isVideo = mainMedia.type === 'video';
+
+  useEffect(() => {
+    const observer = new IntersectionObserver(([entry]) => {
+      if (entry.isIntersecting) { 
+        setIsInView(true); 
+        observer.disconnect(); 
+      }
+    }, { rootMargin: '400px' }); // Larger margin for smoother scrolling
+    
+    if (containerRef.current) {
+      observer.observe(containerRef.current);
+    }
+    return () => observer.disconnect();
+  }, []);
+
+  useEffect(() => {
+    if (!isInView) return;
+
+    if (isVideo) {
+      if (videoThumbnail) return;
+      const video = document.createElement('video');
+      video.src = `${mainMedia.url}#t=0.1`; 
+      video.preload = 'metadata'; 
+      video.muted = true; 
+      video.playsInline = true;
+      
+      const captureFrame = () => {
+        try {
+          const canvas = document.createElement('canvas');
+          canvas.width = video.videoWidth; canvas.height = video.videoHeight;
+          const ctx = canvas.getContext('2d');
+          if (ctx && video.videoWidth > 0) {
+            ctx.drawImage(video, 0, 0, canvas.width, canvas.height);
+            const dataUrl = canvas.toDataURL('image/jpeg', 0.6);
+            videoThumbnailCache.set(mainMedia.url, dataUrl); 
+            setVideoThumbnail(dataUrl);
+          }
+        } catch (err) {} finally { cleanup(); }
+      };
+      
+      const handleLoadedMetadata = () => video.currentTime = 0.1;
+      const handleSeeked = () => captureFrame();
+      const cleanup = () => {
+        video.removeEventListener('loadedmetadata', handleLoadedMetadata);
+        video.removeEventListener('seeked', handleSeeked);
+        video.removeAttribute('src'); 
+        video.load();
+      };
+
+      video.addEventListener('loadedmetadata', handleLoadedMetadata);
+      video.addEventListener('seeked', handleSeeked);
+      video.addEventListener('error', cleanup);
+      const timeout = setTimeout(() => cleanup(), 5000);
+      return () => { clearTimeout(timeout); cleanup(); };
+    } else {
+      // Request high-res image thumbnailing only if size > 1MiB
+      const ONE_MIB = 1024 * 1024;
+      if (mainMedia.size && mainMedia.size > ONE_MIB) {
+        onRequestThumbnail(post.id, mainMedia.url);
+      }
+    }
+  }, [isInView, isVideo, mainMedia.url, mainMedia.size, post.id, onRequestThumbnail, videoThumbnail]);
+
+  // Determine if we are actually expecting a high-res thumbnail
+  const ONE_MIB = 1024 * 1024;
+  const isHighRes = !isVideo && mainMedia.size && mainMedia.size > ONE_MIB;
+  const isGenerating = isHighRes && !thumbnailUrl;
+
+  // Use high-res thumbnail if available, then video thumb, then original
+  const displayUrl = thumbnailUrl || videoThumbnail || post.thumbnail;
+
+  if (!displayUrl && isVideo) {
+    return (
+      <div ref={containerRef} className={cn("w-full h-full bg-gray-100 flex items-center justify-center text-black", className)}>
+        <Play size={20} className="text-gray-300" fill="currentColor" />
+      </div>
+    );
+  }
+
+  if (!displayUrl) {
+    return (
+      <div ref={containerRef} className={cn("w-full h-full bg-gray-50 flex items-center justify-center text-black", className)}>
+        <ImageIcon size={20} className="text-gray-200" />
+      </div>
+    );
+  }
+
+  return (
+    <div ref={containerRef} className="w-full h-full">
+      <img 
+        src={displayUrl} 
+        alt="" 
+        className={cn(
+          "w-full h-full object-cover transition-all duration-700", 
+          className, 
+          isGenerating ? "blur-sm scale-105" : "blur-0 scale-100"
+        )} 
+        referrerPolicy="no-referrer"
+        loading="lazy"
+      />
+    </div>
+  );
+};

src/components/StoryViewer.tsx

@@ -0,0 +1,236 @@
+import React, { useState, useEffect, useRef } from 'react';
+import { 
+  ChevronLeft, 
+  ChevronRight, 
+  Volume2, 
+  VolumeX, 
+  X 
+} from 'lucide-react';
+import { motion } from 'motion/react';
+import { Post } from '../types';
+import { cn, formatDateSafe } from '../lib/utils';
+import { FADE, PRESENT, prefersReducedMotion } from '../lib/motion';
+
+interface StoryViewerProps {
+  stories: Post[];
+  onClose: () => void;
+  profilePic: string | null;
+  /** Highlight name, shown in place of the date when viewing a highlight. */
+  title?: string;
+}
+
+export const StoryViewer: React.FC<StoryViewerProps> = ({
+  stories,
+  onClose,
+  profilePic,
+  title
+}) => {
+  const [currentStoryIndex, setCurrentStoryIndex] = useState(0);
+  const [progress, setProgress] = useState(0);
+  // Opening the reel is a user gesture, so try for sound; the effect below
+  // falls back to muted if the browser refuses, which would otherwise stall
+  // the progress bar on the first video.
+  const [isMuted, setIsMuted] = useState(false);
+  const videoRef = useRef<HTMLVideoElement>(null);
+  const reduceMotion = prefersReducedMotion();
+  const story = stories[currentStoryIndex];
+  const primary = story?.media?.[0];
+
+  useEffect(() => {
+    setProgress(0);
+    let duration = 5000;
+    const interval = 50;
+
+    const updateProgress = () => {
+      if (primary?.type === 'video' && videoRef.current) {
+        const currentTime = videoRef.current.currentTime;
+        const totalTime = videoRef.current.duration;
+        if (totalTime) {
+          setProgress((currentTime / totalTime) * 100);
+        }
+      } else {
+        setProgress(prev => {
+          const step = (interval / duration) * 100;
+          if (prev >= 100) return 100;
+          return prev + step;
+        });
+      }
+    };
+
+    const timer = setInterval(() => {
+      updateProgress();
+    }, interval);
+
+    return () => clearInterval(timer);
+  }, [currentStoryIndex, primary]);
+
+  useEffect(() => {
+    const video = videoRef.current;
+    if (!video || primary?.type !== 'video') return;
+
+    let cancelled = false;
+    video.muted = false;
+    video.play().catch(() => {
+      if (cancelled) return;
+      setIsMuted(true);
+      video.muted = true;
+      video.play().catch(() => { /* leave it to the controls */ });
+    });
+
+    return () => { cancelled = true; };
+  }, [primary]);
+
+  useEffect(() => {
+    if (progress >= 100) {
+      if (currentStoryIndex < stories.length - 1) {
+        setCurrentStoryIndex(prev => prev + 1);
+      } else {
+        onClose();
+      }
+    }
+  }, [progress, currentStoryIndex, stories.length, onClose]);
+
+  const nextStory = () => {
+    if (currentStoryIndex < stories.length - 1) {
+      setCurrentStoryIndex(prev => prev + 1);
+    } else {
+      onClose();
+    }
+  };
+
+  const prevStory = () => {
+    if (currentStoryIndex > 0) {
+      setCurrentStoryIndex(prev => prev - 1);
+    }
+  };
+
+  // An empty or exhausted reel has nothing to show; bail before dereferencing.
+  if (!story || !primary) return null;
+
+  return (
+    <motion.div
+      initial={{ opacity: 0 }}
+      animate={{ opacity: 1 }}
+      exit={{ opacity: 0 }}
+      transition={FADE}
+      className="fixed inset-0 z-[100] bg-[#1a1a1a] flex items-center justify-center overflow-hidden text-white"
+      onClick={onClose}
+    >
+      <div className="absolute inset-0 z-0 text-white">
+        <img 
+          src={primary.url}
+          alt=""
+          className="w-full h-full object-cover blur-3xl opacity-30"
+        />
+      </div>
+
+      <button 
+        onClick={(e) => { e.stopPropagation(); prevStory(); }}
+        className={cn(
+          "hidden md:flex absolute left-4 lg:left-20 z-50 text-white/80 hover:text-white transition-all bg-white/10 p-3 rounded-full backdrop-blur-md",
+          currentStoryIndex === 0 && "opacity-0 pointer-events-none"
+        )}
+      >
+        <ChevronLeft size={32} strokeWidth={1.5} />
+      </button>
+
+      <button 
+        onClick={(e) => { e.stopPropagation(); nextStory(); }}
+        className="hidden md:flex absolute right-4 lg:right-20 z-50 text-white/80 hover:text-white transition-all bg-white/10 p-3 rounded-full backdrop-blur-md"
+      >
+        <ChevronRight size={32} strokeWidth={1.5} />
+      </button>
+
+      <motion.div
+        initial={reduceMotion ? false : { scale: 0.94, opacity: 0 }}
+        animate={{ scale: 1, opacity: 1 }}
+        exit={reduceMotion ? { opacity: 0 } : { scale: 0.94, opacity: 0 }}
+        transition={PRESENT}
+        className="relative w-full h-full md:h-[90vh] md:max-w-[45vh] bg-black overflow-hidden md:rounded-lg shadow-2xl z-10 text-white"
+        onClick={e => e.stopPropagation()}
+      >
+        <div 
+          className="absolute top-2 left-2 right-2 z-50 flex px-1 text-white"
+          style={{ gap: stories.length > 100 ? '1px' : (stories.length > 50 ? '2px' : '4px') }}
+        >
+          {stories.map((_, i) => (
+            <div key={i} className="h-1 flex-1 bg-white/20 rounded-full overflow-hidden text-white">
+              <div 
+                className="h-full bg-white transition-all duration-75 text-white"
+                style={{ 
+                  width: i < currentStoryIndex ? '100%' : (i === currentStoryIndex ? `${progress}%` : '0%') 
+                }}
+              />
+            </div>
+          ))}
+        </div>
+
+        <div className="absolute top-6 left-4 right-4 z-50 flex items-center justify-between text-white">
+          <div className="flex items-center gap-2">
+            <div className="w-8 h-8 rounded-full bg-white/10 p-0.5">
+              <div className="w-full h-full rounded-full bg-gray-200 flex items-center justify-center overflow-hidden">
+                {profilePic ? (
+                  <img src={profilePic} alt="" className="w-full h-full object-cover text-black" referrerPolicy="no-referrer" />
+                ) : (
+                  <span className="text-[10px] font-bold text-black uppercase">{story.username[0]}</span>
+                )}
+              </div>
+            </div>
+            <div className="flex items-center gap-2 text-white">
+              <span className="text-xs font-semibold">{story.username}</span>
+              {title && <span className="text-[10px] opacity-80 font-medium truncate max-w-[120px]">{title}</span>}
+              <span className="text-[10px] opacity-60 font-medium">{formatDateSafe(story.date, 'MMM d')}</span>
+            </div>
+          </div>
+          
+          <div className="flex items-center gap-1 text-white">
+            {primary.type === 'video' && (
+              <button 
+                onClick={(e) => { e.stopPropagation(); setIsMuted(!isMuted); }}
+                className="p-2 hover:bg-white/10 rounded-full transition-colors text-white"
+              >
+                {isMuted ? <VolumeX size={20} /> : <Volume2 size={20} />}
+              </button>
+            )}
+            <button onClick={onClose} className="p-2 hover:bg-white/10 rounded-full transition-colors text-white">
+              <X size={24} />
+            </button>
+          </div>
+        </div>
+
+        <div className="w-full h-full flex items-center justify-center pointer-events-none text-white">
+          {primary.type === 'video' ? (
+            <video 
+              ref={videoRef}
+              src={primary.url}
+              className="w-full h-full object-contain"
+              autoPlay 
+              muted={isMuted}
+              playsInline
+              controls
+              onEnded={nextStory}
+            />
+          ) : (
+            <img 
+              src={primary.url}
+              alt=""
+              className="w-full h-full object-contain"
+              referrerPolicy="no-referrer"
+            />
+          )}
+        </div>
+
+        <div className="absolute inset-0 z-20 flex">
+          <div className="w-1/4 h-full cursor-pointer" onClick={prevStory} title="Previous Story" />
+          <div className="w-3/4 h-full cursor-pointer" onClick={nextStory} title="Next Story" />
+        </div>
+
+        {story.caption && (
+          <div className="absolute bottom-16 left-4 right-4 z-50 bg-black/20 backdrop-blur-sm p-3 rounded-lg text-white text-xs text-center border border-white/10">
+            {story.caption}
+          </div>
+        )}
+      </motion.div>
+    </motion.div>
+  );
+};

src/hooks/useArchiveScanner.ts

@@ -0,0 +1,497 @@
+import { useState, useCallback, useRef, useEffect } from 'react';
+// @ts-ignore
+import { XzReadableStream } from 'xz-decompress';
+import { ArchiveFile, CacheData, Post, ServerArchive } from '../types';
+import { setCachedArchive, getDirectoryHandle } from '../lib/archive-cache';
+import { parseArchiveFilename, scopedPostId, EXPORT_RE, INSTALOADER_RE } from '../lib/archive-patterns';
+
+const hasDirectoryHandle = async (name: string) => Boolean(await getDirectoryHandle(name));
+
+export const useArchiveScanner = (
+  detectedUsername: string,
+  currentArchive: ServerArchive | null,
+  refreshCachedArchives: () => Promise<void>
+) => {
+  const [isScanning, setIsScanning] = useState(false);
+  const [scanningPhase, setScanningPhase] = useState<'Indexing' | 'Parsing' | 'Checking Cache' | ''>('');
+  const [scannedCount, setScannedCount] = useState(0);
+  const [totalFiles, setTotalFiles] = useState(0);
+  const [scannedFilesLog, setScannedFilesLog] = useState<string[]>([]);
+  const [currentScanningImage, setCurrentScanningImage] = useState<string | null>(null);
+
+  // Result state
+  const [allPosts, setAllPosts] = useState<Post[]>([]);
+  const [allStories, setAllStories] = useState<Post[]>([]);
+  const [allHighlights, setAllHighlights] = useState<Post[]>([]);
+  const [profileMetadata, setProfileMetadata] = useState<{
+    username: string;
+    fullName: string;
+    bio: string;
+    followerCount: number;
+    followingCount: number;
+    externalUrl: string;
+    profilePic: string | null;
+    allProfilePics: string[];
+  }>({
+    username: '',
+    fullName: '',
+    bio: '',
+    followerCount: 0,
+    followingCount: 0,
+    externalUrl: '',
+    profilePic: null,
+    allProfilePics: [],
+  });
+
+  /**
+   * Blob URLs minted for the archive currently in state. They stay alive as long
+   * as that archive is on screen and are released when it is torn down —
+   * otherwise every archive ever opened stays resident for the tab's lifetime.
+   */
+  const createdUrlsRef = useRef<string[]>([]);
+
+  const revokeCreatedUrls = useCallback(() => {
+    for (const url of createdUrlsRef.current) {
+      try { URL.revokeObjectURL(url); } catch { /* already gone */ }
+    }
+    createdUrlsRef.current = [];
+  }, []);
+
+  // Release the last archive's URLs when the app unmounts.
+  useEffect(() => revokeCreatedUrls, [revokeCreatedUrls]);
+
+  /** Hand ownership of an externally-minted blob URL to the scanner's cleanup. */
+  const registerUrl = useCallback((url: string) => {
+    createdUrlsRef.current.push(url);
+  }, []);
+
+  const resetScannerState = useCallback(() => {
+    revokeCreatedUrls();
+    setAllPosts([]);
+    setAllStories([]);
+    setAllHighlights([]);
+    setProfileMetadata({
+      username: '',
+      fullName: '',
+      bio: '',
+      followerCount: 0,
+      followingCount: 0,
+      externalUrl: '',
+      profilePic: null,
+      allProfilePics: [],
+    });
+  }, [revokeCreatedUrls]);
+
+  const handleFiles = useCallback(async (files: ArchiveFile[], archiveContext?: ServerArchive) => {
+    if (!files || files.length === 0) return;
+    setIsScanning(true);
+    resetScannerState();
+    setScanningPhase('Indexing');
+    setScannedCount(0);
+    setTotalFiles(files.length);
+    setScannedFilesLog([]);
+    
+    console.log(`[Scanner] Starting scan of ${files.length} files...`);
+    await new Promise(resolve => setTimeout(resolve, 100));
+
+    /**
+     * Mint a URL for a media file, remembering it if it needs revoking later.
+     * Synchronous and allocation-free: no file contents are read here.
+     */
+    const mintUrl = (file: ArchiveFile, mimeHint?: string) => {
+      const url = file.createObjectUrl(mimeHint);
+      if (file.revocable) createdUrlsRef.current.push(url);
+      return url;
+    };
+
+    /** Stable identity for a media file, used to rehydrate URLs after a reload. */
+    const mediaPath = (file: ArchiveFile) => file.webkitRelativePath || file.name;
+
+    /**
+     * Decompress an `.xz` metadata sidecar.
+     *
+     * Read fully into memory first rather than handing the live HTTP body to
+     * the decompressor. These sidecars are a few KB, so buffering costs
+     * nothing, and streaming was actively harmful: the decompressor stops
+     * reading at the end of the xz member, leaving the response body neither
+     * drained nor cancelled. Across a couple of hundred sidecars that exhausts
+     * the connection pool and every later fetch fails with "Failed to fetch" —
+     * which silently cost Instaloader archives their captions, story flags and
+     * profile metadata, since all of it lives in these files.
+     */
+    const parseXZFile = async (file: ArchiveFile) => {
+      try {
+        const compressed = await file.arrayBuffer();
+        const stream = new XzReadableStream(new Blob([compressed]).stream());
+        return await new Response(stream).json();
+      } catch (e) { console.error(`[Scanner] XZ Parse Error:`, file.name, e); return null; }
+    };
+
+    let lastImageUpdateTime = 0;
+    const throttledSetScanningImage = (url: string) => {
+      const now = Date.now();
+      if (now - lastImageUpdateTime > 1000) {
+        setCurrentScanningImage(url);
+        lastImageUpdateTime = now;
+      }
+    };
+
+    const isImage = (name: string) => /\.(jpg|jpeg|png|webp|gif|bmp|svg|tiff)$/i.test(name);
+    const isVideo = (name: string) => /\.(mp4|webm|ogv|mov)$/i.test(name);
+    const isMedia = (name: string) => isImage(name) || isVideo(name);
+
+    try {
+      const postsMap = new Map<string, Partial<Post>>();
+      const mediaFilesMap = new Map<string, ArchiveFile>();
+      const discoveredProfilePics: { name: string, url: string }[] = [];
+      const allImageFiles: ArchiveFile[] = [];
+      
+      let localFullName = '';
+      let localBio = '';
+      let localExternalUrl = '';
+      let localFollowerCount = 0;
+      let localFollowingCount = 0;
+      let localProfilePic: string | null = null;
+
+      const checkIsStory = (obj: any): boolean => {
+        if (!obj) return false;
+        const typeName = obj.__typename || obj.typename || '';
+        return (obj.is_story === true || obj.is_reel_media === true || typeName.includes('Story') || obj.audience === "MediaAudience.DEFAULT" || obj.node_type === "StoryItem" || obj.product_type === "story" || typeName === "GraphStoryVideo" || typeName === "GraphStoryImage");
+      };
+
+      let currentUsername = archiveContext?.name || currentArchive?.name || detectedUsername;
+      
+      // If still no username (likely local folder), try to extract from path
+      if (!currentUsername && files[0]?.webkitRelativePath) {
+        const pathParts = files[0].webkitRelativePath.split(/[/\\]/);
+        if (pathParts.length > 1) {
+          currentUsername = pathParts[0];
+        }
+      }
+      
+      if (!currentUsername) currentUsername = 'archived_user';
+
+      let format: 'export' | 'instaloader' | 'json' | 'unknown' = 'unknown';
+      let jsonFiles: ArchiveFile[] = [];
+
+      // Pass 1: Indexing
+      for (let i = 0; i < files.length; i++) {
+        const file = files[i];
+        if (i % 100 === 0 || i === files.length - 1) {
+          setScannedCount(i + 1);
+          setScannedFilesLog(prev => [`Indexed ${file.name}`, ...prev.slice(0, 19)]);
+          // Yield to main thread
+          await new Promise(resolve => setTimeout(resolve, 0));
+        }
+        const lowerName = file.name.toLowerCase();
+        
+        if (lowerName.endsWith('.json') || lowerName.endsWith('.json.xz')) {
+          jsonFiles.push(file);
+          if (lowerName.includes('posts_1') || lowerName.includes('reels_1') || lowerName.includes('stories_1')) format = 'json';
+          continue;
+        }
+
+        if (EXPORT_RE.test(file.name)) format = 'export';
+        else if (INSTALOADER_RE.test(file.name)) format = 'instaloader';
+        // Highlight items match neither pattern, so a profile made up only of
+        // sidecar directories would otherwise never reach the filename parser.
+        else if (format === 'unknown' && file.source && file.source.kind !== 'posts') format = 'export';
+
+        if (lowerName.includes('_profile_pic.jpg') || (currentUsername && lowerName === `${currentUsername.toLowerCase()}.jpg`)) {
+          try {
+            const url = mintUrl(file, 'image/jpeg');
+            discoveredProfilePics.push({ name: file.name, url });
+            if (format === 'unknown' && lowerName.includes('_profile_pic.jpg')) format = 'instaloader';
+          } catch(e) {}
+        }
+
+        if (isMedia(file.name)) {
+          mediaFilesMap.set(file.webkitRelativePath || file.name, file);
+          if (isImage(file.name)) allImageFiles.push(file);
+        }
+      }
+
+      console.log(`[Scanner] Format Detection Complete. Result: ${format}. Media indexed: ${mediaFilesMap.size}`);
+
+      if (jsonFiles.length > 0 && (format === 'json' || format === 'instaloader')) {
+        setScanningPhase('Parsing');
+        for (let i = 0; i < jsonFiles.length; i++) {
+          const jsonFile = jsonFiles[i];
+          setScannedCount(i + 1);
+          setScannedFilesLog(prev => [`Parsing ${jsonFile.name}`, ...prev.slice(0, 19)]);
+          try {
+            const data = jsonFile.name.endsWith('.xz') ? await parseXZFile(jsonFile) : JSON.parse(await jsonFile.text());
+            if (!data) continue;
+            const items = Array.isArray(data) ? data : (data.media || [data]);
+            const isStoriesFile = jsonFile.name.toLowerCase().includes('stories');
+
+            if (data.node && (data.instaloader?.node_type === 'Profile' || data.node.__typename === 'User')) {
+              const node = data.node; const iphone = node.iphone_struct || {};
+              localFullName = node.full_name || ''; localBio = node.biography || iphone.biography || '';
+              localExternalUrl = node.external_url || '';
+              localFollowerCount = node.edge_followed_by?.count || iphone.follower_count || 0;
+              localFollowingCount = node.edge_follow?.count || iphone.following_count || 0;
+              if (!Array.isArray(data)) continue;
+            }
+
+            for (const [idx, item] of items.entries()) {
+              const mediaList = item.media || [item];
+              const postId = item.node?.id || item.id || item.title || `post_${idx}_${Date.now()}`;
+              const date = item.creation_timestamp ? new Date(item.creation_timestamp * 1000).toISOString().split('T')[0] : (item.node?.taken_at_timestamp ? new Date(item.node.taken_at_timestamp * 1000).toISOString().split('T')[0] : new Date().toISOString().split('T')[0]);
+              const isStory = isStoriesFile || checkIsStory(item) || checkIsStory(item.node) || checkIsStory(data.instaloader) || checkIsStory(item.node?.iphone_struct) || checkIsStory(item.iphone_struct) || (item.media && Array.isArray(item.media) && item.media.some((m: any) => checkIsStory(m)));
+              const post: Partial<Post> = { id: postId, date, username: currentUsername || 'archived_user', caption: item.title || item.node?.edge_media_to_caption?.edges?.[0]?.node?.text || item.node?.caption?.text || '', media: [], isStory };
+
+              for (const [mIdx, m] of mediaList.entries()) {
+                const uri = m.uri; let matchedFile: ArchiveFile | undefined;
+                if (uri) { for (const [path, f] of mediaFilesMap.entries()) { if (path.endsWith(uri) || uri.endsWith(path)) { matchedFile = f; break; } } }
+                if (!matchedFile) { const id = item.node?.id || item.id; if (id) { for (const [path, f] of mediaFilesMap.entries()) { if (f.name.includes(id)) { matchedFile = f; break; } } } }
+                if (!matchedFile) { 
+                  const jsonBase = jsonFile.name.substring(0, jsonFile.name.lastIndexOf('.'));
+                  for (const ext of ['mp4', 'webm', 'jpg', 'jpeg', 'png', 'webp', 'gif']) {
+                    const possibleName = `${jsonBase}.${ext}`;
+                    for (const [path, f] of mediaFilesMap.entries()) { if (f.name.toLowerCase() === possibleName.toLowerCase()) { matchedFile = f; break; } }
+                    if (matchedFile) break;
+                  }
+                }
+
+                if (matchedFile) {
+                  const type = isVideo(matchedFile.name) ? 'video' : 'image';
+                  const url = mintUrl(matchedFile, type === 'video' ? 'video/mp4' : 'image/jpeg');
+                  const existingMedia = post.media!.find(media => media.index === mIdx + 1);
+                  if (existingMedia) { if (type === 'video' && existingMedia.type === 'image') post.media = post.media!.map(media => media.index === mIdx + 1 ? { name: matchedFile!.name, path: mediaPath(matchedFile!), url, type, index: mIdx + 1, size: matchedFile!.size } : media); }
+                  else post.media!.push({ name: matchedFile.name, path: mediaPath(matchedFile), url, type, index: mIdx + 1, size: matchedFile.size });
+                }
+              }
+              if (post.media!.length > 0) postsMap.set(postId, post);
+            }
+          } catch (e) { console.error(`[Scanner] Error parsing JSON ${jsonFile.name}:`, e); }
+          // Yield to main thread
+          if (i % 10 === 0) await new Promise(resolve => setTimeout(resolve, 0));
+        }
+      } 
+      
+      if (format === 'export' || format === 'instaloader') {
+        setScanningPhase('Parsing');
+        const CHUNK_SIZE = 100;
+        for (let j_start = 0; j_start < files.length; j_start += CHUNK_SIZE) {
+          const end = Math.min(j_start + CHUNK_SIZE, files.length);
+          setScannedCount(j_start);
+          setScannedFilesLog(prev => [`Batch ${Math.floor(j_start/CHUNK_SIZE) + 1} processing...`, ...prev.slice(0, 19)]);
+          for (let j = j_start; j < end; j++) {
+            const file = files[j]; const lowerName = file.name.toLowerCase();
+            const kind = file.source?.kind ?? 'posts';
+            const parsed = parseArchiveFilename(file.name, kind, file.mtime);
+            if (!parsed) continue;
+
+            const { date, index, ext } = parsed;
+            const user = parsed.username || currentUsername || 'archived_user';
+            let isStory = parsed.isStory
+              || lowerName.includes('story')
+              || file.webkitRelativePath.toLowerCase().includes('stories');
+
+            const postId = scopedPostId(parsed.postId, kind, file.source?.dir);
+            if (kind === 'stories') isStory = true;
+            if (kind === 'highlight') isStory = false;
+
+            let post = postsMap.get(postId);
+            if (!post) {
+              post = { id: postId, date, username: user, caption: '', media: [], isStory, source: kind, highlightTitle: file.source?.title };
+              postsMap.set(postId, post);
+            }
+            else if (isStory) post.isStory = true;
+
+            const lowerExt = ext.toLowerCase();
+            if (lowerExt === 'txt') {
+              try { post.caption = await file.text(); } catch(e) {}
+            } else if (lowerExt === 'json' || lowerName.endsWith('.json.xz')) {
+              try {
+                const data = lowerName.endsWith('.xz') ? await parseXZFile(file) : JSON.parse(await file.text());
+                if (data) {
+                  const node = data.node || data; const iphone = node.iphone_struct || {};
+                  const captionText = node.edge_media_to_caption?.edges?.[0]?.node?.text || node.caption?.text || iphone.caption?.text || '';
+                  if (captionText) post.caption = captionText;
+                  if (checkIsStory(data) || checkIsStory(node) || checkIsStory(data.instaloader) || checkIsStory(iphone)) post.isStory = true;
+                }
+              } catch (e) {}
+            } else if (isMedia(file.name)) {
+              const type = isVideo(file.name) ? 'video' : 'image';
+              const url = mintUrl(file, type === 'video' ? 'video/mp4' : 'image/jpeg');
+              if (type === 'image') throttledSetScanningImage(url);
+              const existingMedia = post.media!.find(m => m.index === index);
+              if (existingMedia) { if (type === 'video' && existingMedia.type === 'image') post.media = post.media!.map(m => m.index === index ? { name: file.name, path: mediaPath(file), url, type, index, size: file.size } : m); }
+              else post.media!.push({ name: file.name, path: mediaPath(file), url, type, index, size: file.size });
+            }
+          }
+          await new Promise(resolve => setTimeout(resolve, 0));
+        }
+      }
+
+      if (postsMap.size === 0) {
+        console.log(`[Scanner] No posts found with standard patterns. Using mediaFilesMap: ${mediaFilesMap.size}`);
+        setScanningPhase('Parsing');
+        const genericGroupingMap = new Map<string, ArchiveFile[]>();
+        for (const [key, file] of mediaFilesMap.entries()) {
+          const match = file.name.match(/^(.*?)(?:(_|-|\s)+(\d+))?\.(.+)$/);
+          let baseName = file.name;
+          if (match && match[3]) { baseName = match[1].trim(); }
+          else { baseName = file.name.substring(0, file.name.lastIndexOf('.')); }
+          if (!genericGroupingMap.has(baseName)) genericGroupingMap.set(baseName, []);
+          genericGroupingMap.get(baseName)!.push(file);
+        }
+        console.log(`[Scanner] Generic grouping found ${genericGroupingMap.size} base groups.`);
+        let processedGroups = 0;
+        const groupEntries = Array.from(genericGroupingMap.entries());
+        for (const [baseName, groupFiles] of groupEntries) {
+          processedGroups++;
+          if (processedGroups % 10 === 0 || processedGroups === genericGroupingMap.size) {
+            setScannedCount(Math.floor((processedGroups / (genericGroupingMap.size || 1)) * (files.length || 1)));
+            setScannedFilesLog(prev => [`Grouping: ${baseName}`, ...prev.slice(0, 19)]);
+            await new Promise(resolve => setTimeout(resolve, 0));
+          }
+          groupFiles.sort((a, b) => {
+            const na = a.name.match(/[_-](\d+)\.\w+$/)?.[1];
+            const nb = b.name.match(/[_-](\d+)\.\w+$/)?.[1];
+            if (na && nb) return parseInt(na, 10) - parseInt(nb, 10);
+            return a.name.localeCompare(b.name);
+          });
+          const CAROUSEL_MAX = 20;
+          for (let j = 0; j < groupFiles.length; j += CAROUSEL_MAX) {
+            const batch = groupFiles.slice(j, j + CAROUSEL_MAX);
+            const partSuffix = groupFiles.length > CAROUSEL_MAX ? `_part${Math.floor(j/CAROUSEL_MAX) + 1}` : '';
+            const postId = `${baseName}${partSuffix}`;
+            const post: Post = { id: postId, date: new Date().toISOString().split('T')[0], username: currentUsername || 'archived_user', caption: baseName, media: [], thumbnail: '' };
+            for (const [idx, file] of batch.entries()) {
+              const type = isVideo(file.name) ? 'video' : 'image';
+              const url = mintUrl(file, type === 'video' ? 'video/mp4' : 'image/jpeg');
+              if (type === 'image') throttledSetScanningImage(url);
+              post.media.push({ name: file.name, path: mediaPath(file), url, type, index: idx + 1, size: file.size });
+            }
+            post.thumbnail = post.media[0].url;
+            postsMap.set(postId, post);
+          }
+        }
+      }
+
+      if (discoveredProfilePics.length > 0) {
+        discoveredProfilePics.sort((a, b) => b.name.localeCompare(a.name));
+        const urls = discoveredProfilePics.map(p => p.url);
+        localProfilePic = urls[0];
+        setProfileMetadata(prev => ({ ...prev, profilePic: localProfilePic, allProfilePics: urls }));
+      } else if (allImageFiles.length > 0) {
+        // Fallback: Use oldest image in archive as profile pic
+        allImageFiles.sort((a, b) => a.name.localeCompare(b.name));
+        const oldestFile = allImageFiles[0];
+        try {
+          const url = mintUrl(oldestFile, 'image/jpeg');
+          localProfilePic = url;
+          setProfileMetadata(prev => ({ ...prev, profilePic: localProfilePic, allProfilePics: [url] }));
+        } catch(e) {}
+      }
+
+      const finalUsername = currentUsername || 'archived_user';
+      const allItems = Array.from(postsMap.values()).filter(p => p.media && p.media.length > 0).map(p => {
+        const sortedMedia = p.media!.sort((a, b) => a.index - b.index);
+        return { ...p, username: (p.username === 'archived_user' || !p.username) ? finalUsername : p.username, media: sortedMedia, thumbnail: sortedMedia[0].url } as Post;
+      });
+
+      const byNewest = (a: Post, b: Post) => b.date.localeCompare(a.date);
+      // Highlights are story-shaped but live behind their own circles, so they
+      // are kept out of both the grid and the profile-ring story reel.
+      const highlights = allItems.filter(p => p.source === 'highlight').sort(byNewest);
+      const rest = allItems.filter(p => p.source !== 'highlight');
+      const posts = rest.filter(p => !p.isStory).sort(byNewest);
+      const stories = rest.filter(p => p.isStory).sort(byNewest);
+
+      setAllPosts(posts);
+      setAllStories(stories);
+      setAllHighlights(highlights);
+      setProfileMetadata(prev => ({
+        ...prev,
+        username: finalUsername,
+        fullName: localFullName,
+        bio: localBio,
+        followerCount: localFollowerCount,
+        followingCount: localFollowingCount,
+        externalUrl: localExternalUrl,
+        profilePic: localProfilePic || prev.profilePic,
+      }));
+
+      console.log(`[Scanner] Finalized ${posts.length} posts and ${stories.length} stories.`);
+
+      const archiveToCache = archiveContext || currentArchive;
+      const isLocal = !archiveToCache;
+      const cacheKey = archiveToCache ? archiveToCache.name : (finalUsername || 'local_archive');
+
+      if (cacheKey && (posts.length > 0 || stories.length > 0)) {
+        console.log(`[Cache] Saving data for ${cacheKey} to persistent storage...`);
+        let cacheThumbnail = localProfilePic;
+        if (isLocal && posts.length > 0 && posts[0].media[0].type === 'image') {
+          try {
+            const img = new Image(); img.src = posts[0].media[0].url;
+            await new Promise((res) => { img.onload = res; img.onerror = res; });
+            if (img.complete && img.width > 0) {
+              const canvas = document.createElement('canvas'); const size = 200;
+              canvas.width = size; canvas.height = size;
+              const ctx = canvas.getContext('2d');
+              if (ctx) { ctx.drawImage(img, 0, 0, img.width, img.height, 0, 0, size, size); cacheThumbnail = canvas.toDataURL('image/jpeg', 0.7); }
+            }
+          } catch (e) {}
+        }
+
+        const cacheData: CacheData = {
+          name: cacheKey, isLocal,
+          fileCount: (archiveToCache ? archiveToCache.fileCount : files.length) ?? files.length,
+          signature: archiveToCache?.signature,
+          posts: posts,
+          stories: stories,
+          highlights: highlights,
+          profileMetadata: {
+            username: finalUsername,
+            fullName: localFullName,
+            bio: localBio,
+            followerCount: localFollowerCount,
+            followingCount: localFollowingCount,
+            externalUrl: localExternalUrl,
+            // Local blob: URLs die with the document, so persist a data: URL for
+            // the dashboard card instead. Media URLs are rehydrated from `path`.
+            profilePic: isLocal ? cacheThumbnail : localProfilePic,
+            allProfilePics: isLocal ? (cacheThumbnail ? [cacheThumbnail] : []) : discoveredProfilePics.map(p => p.url)
+          },
+          hasDirectoryHandle: isLocal ? await hasDirectoryHandle(cacheKey) : false,
+          timestamp: Date.now()
+        };
+        try {
+          await setCachedArchive(cacheData);
+          console.log(`[Cache] Data saved successfully.`);
+          await refreshCachedArchives();
+        } catch (e) { console.error(`[Cache] Save error:`, e); }
+      }
+    } catch (err) { console.error(`[Scanner] Critical error during scan:`, err); } finally { setIsScanning(false); }
+  }, [currentArchive, detectedUsername, resetScannerState, refreshCachedArchives]);
+
+  return {
+    isScanning,
+    scanningPhase,
+    scannedCount,
+    totalFiles,
+    scannedFilesLog,
+    currentScanningImage,
+    allPosts,
+    allStories,
+    allHighlights,
+    profileMetadata,
+    handleFiles,
+    setAllPosts,
+    setAllStories,
+    setAllHighlights,
+    setProfileMetadata,
+    setIsScanning,
+    setScanningPhase,
+    setScannedCount,
+    setTotalFiles,
+    setScannedFilesLog,
+    setCurrentScanningImage,
+    resetScannerState,
+    registerUrl
+  };
+};

src/hooks/useIsMobile.ts

@@ -0,0 +1,27 @@
+import { useEffect, useState } from 'react';
+
+/** Matches Tailwind's `md` breakpoint, the point where the layout splits. */
+const MOBILE_QUERY = '(max-width: 767px)';
+
+/**
+ * True on phone-sized viewports.
+ *
+ * Drives more than styling: mobile opens posts as a scrollable feed page while
+ * desktop uses the modal, so this needs to be real state rather than a CSS
+ * media query.
+ */
+export const useIsMobile = () => {
+  const [isMobile, setIsMobile] = useState(
+    () => typeof window !== 'undefined' && window.matchMedia(MOBILE_QUERY).matches,
+  );
+
+  useEffect(() => {
+    const query = window.matchMedia(MOBILE_QUERY);
+    const onChange = (e: MediaQueryListEvent) => setIsMobile(e.matches);
+    query.addEventListener('change', onChange);
+    setIsMobile(query.matches);
+    return () => query.removeEventListener('change', onChange);
+  }, []);
+
+  return isMobile;
+};

src/hooks/useThumbnailQueue.ts

@@ -0,0 +1,128 @@
+import { useState, useCallback, useRef, useEffect } from 'react';
+import * as idb from 'idb-keyval';
+import { thumbKey } from '../lib/archive-cache';
+
+interface ThumbnailRequest {
+  id: string;
+  key: string;
+  url: string;
+  blob?: Blob;
+}
+
+const THUMBNAIL_WIDTH = 400;
+
+export const useThumbnailQueue = (archiveName: string) => {
+  const [cacheHits, setCacheHits] = useState<Map<string, string>>(new Map());
+  const queueRef = useRef<ThumbnailRequest[]>([]);
+  const isProcessingRef = useRef(false);
+  const workerRef = useRef<Worker | null>(null);
+
+  /**
+   * Mirrors `cacheHits` for reads inside callbacks.
+   *
+   * `requestThumbnail` is a dependency of every PostThumbnail effect, so it must
+   * keep a stable identity — closing over `cacheHits` state directly would give
+   * it a new identity per completed thumbnail and re-run the effect in all
+   * ~90 mounted thumbnails each time.
+   */
+  const cacheHitsRef = useRef<Map<string, string>>(new Map());
+  /** Blob URLs handed out for thumbnails, released when the archive changes. */
+  const createdUrlsRef = useRef<string[]>([]);
+
+  const publish = useCallback((id: string, url: string) => {
+    createdUrlsRef.current.push(url);
+    cacheHitsRef.current.set(id, url);
+    setCacheHits(new Map(cacheHitsRef.current));
+  }, []);
+
+  const processNext = useCallback(async () => {
+    if (isProcessingRef.current || queueRef.current.length === 0 || !workerRef.current) return;
+
+    isProcessingRef.current = true;
+    const request = queueRef.current.shift()!;
+
+    try {
+      // Re-check the store: the entry may have landed since being queued.
+      const cached = await idb.get(request.key);
+      if (cached instanceof Blob) {
+        publish(request.id, URL.createObjectURL(cached));
+        isProcessingRef.current = false;
+        processNext();
+        return;
+      }
+
+      let blob = request.blob;
+      if (!blob) {
+        const res = await fetch(request.url);
+        blob = await res.blob();
+      }
+
+      // One image at a time: decoding several 50MP+ files concurrently is a
+      // reliable way to OOM the tab.
+      workerRef.current.postMessage({ id: request.key, blob, width: THUMBNAIL_WIDTH });
+    } catch (err) {
+      console.error('[ThumbnailQueue] Failed to process:', request.id, err);
+      isProcessingRef.current = false;
+      processNext();
+    }
+  }, [publish]);
+
+  useEffect(() => {
+    workerRef.current = new Worker(new URL('../lib/thumbnail-worker.ts', import.meta.url), {
+      type: 'module'
+    });
+
+    workerRef.current.onmessage = async (e) => {
+      const { id: key, blob, error } = e.data;
+
+      if (!error && blob) {
+        const id = key.split(':').slice(2).join(':');
+        publish(id, URL.createObjectURL(blob));
+        try {
+          await idb.set(key, blob);
+        } catch (err) { /* quota exceeded; the in-memory hit still stands */ }
+      }
+
+      isProcessingRef.current = false;
+      processNext();
+    };
+
+    return () => {
+      workerRef.current?.terminate();
+    };
+  }, [publish, processNext]);
+
+  // Switching archives invalidates every thumbnail URL handed out so far.
+  useEffect(() => {
+    return () => {
+      queueRef.current = [];
+      for (const url of createdUrlsRef.current) {
+        try { URL.revokeObjectURL(url); } catch { /* already gone */ }
+      }
+      createdUrlsRef.current = [];
+      cacheHitsRef.current = new Map();
+      setCacheHits(new Map());
+    };
+  }, [archiveName]);
+
+  const requestThumbnail = useCallback(async (id: string, url: string, blob?: Blob) => {
+    if (cacheHitsRef.current.has(id)) return;
+
+    const key = thumbKey(archiveName, id);
+    const cached = await idb.get(key);
+    if (cached instanceof Blob) {
+      publish(id, URL.createObjectURL(cached));
+      return;
+    }
+
+    if (!queueRef.current.some(r => r.id === id)) {
+      queueRef.current.push({ id, key, url, blob });
+      processNext();
+    }
+  }, [archiveName, publish, processNext]);
+
+  return {
+    cacheHits,
+    requestThumbnail
+  };
+};

src/index.css

@@ -1,4 +1,5 @@
-@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&family=Playfair+Display:ital,wght@0,400..900;1,400..900&display=swap');
+/* Self-hosted: no third-party font requests, works fully offline. */
+@import url('/fonts/fonts.css');
 @import "tailwindcss";
 
 @theme {

src/lib/archive-cache.ts

@@ -0,0 +1,170 @@
+import * as idb from 'idb-keyval';
+import { CacheData, Post } from '../types';
+import { DirectoryHandle, ensureReadPermission, filesFromDirectory } from './directory-handle';
+import { LocalArchiveFile } from './archive-files';
+
+/**
+ * Persistent archive cache.
+ *
+ * Keys are namespaced so that listing archives does not require deserializing
+ * every thumbnail blob in the store: `archive:` entries are metadata, `thumb:`
+ * entries are image blobs, `handle:` entries are directory handles.
+ */
+const ARCHIVE_PREFIX = 'archive:';
+const THUMB_PREFIX = 'thumb:';
+const HANDLE_PREFIX = 'handle:';
+
+export const archiveKey = (name: string) => `${ARCHIVE_PREFIX}${name}`;
+export const handleKey = (name: string) => `${HANDLE_PREFIX}${name}`;
+/** Thumbnails are scoped per archive; post IDs alone collide across archives. */
+export const thumbKey = (archive: string, postId: string) => `${THUMB_PREFIX}${archive}:${postId}`;
+
+export const getCachedArchive = (name: string): Promise<CacheData | undefined> =>
+  idb.get(archiveKey(name));
+
+export const setCachedArchive = (data: CacheData) => idb.set(archiveKey(data.name), data);
+
+/** Names of all cached archives, without loading their contents. */
+export const listCachedArchiveNames = async (): Promise<string[]> =>
+  (await idb.keys())
+    .map(String)
+    .filter(k => k.startsWith(ARCHIVE_PREFIX))
+    .map(k => k.slice(ARCHIVE_PREFIX.length));
+
+export const listCachedArchives = async (): Promise<CacheData[]> => {
+  const names = await listCachedArchiveNames();
+  const entries = await Promise.all(names.map(getCachedArchive));
+  return entries.filter((e): e is CacheData => Boolean(e));
+};
+
+/** Remove an archive along with its handle and every thumbnail it owns. */
+export const deleteCachedArchive = async (name: string) => {
+  const thumbPrefix = `${THUMB_PREFIX}${name}:`;
+  const stale = (await idb.keys()).map(String).filter(k => k.startsWith(thumbPrefix));
+  await idb.delMany([archiveKey(name), handleKey(name), ...stale]);
+};
+
+export const saveDirectoryHandle = (name: string, handle: DirectoryHandle) =>
+  idb.set(handleKey(name), handle);
+
+export const getDirectoryHandle = (name: string): Promise<DirectoryHandle | undefined> =>
+  idb.get(handleKey(name));
+
+/**
+ * One-time migration from the flat key layout (archive name as a bare key,
+ * `thumb_<postId>` for thumbnails).
+ *
+ * Old local entries are dropped rather than migrated: their media URLs are
+ * dead blob: URLs, so restoring them would render an archive of broken images.
+ */
+export const migrateLegacyCache = async () => {
+  const keys = (await idb.keys()).map(String);
+  const legacyThumbs = keys.filter(k => k.startsWith('thumb_'));
+  const legacyArchives = keys.filter(
+    k => !k.startsWith(ARCHIVE_PREFIX) && !k.startsWith(THUMB_PREFIX) &&
+         !k.startsWith(HANDLE_PREFIX) && !k.startsWith('thumb_')
+  );
+  if (!legacyThumbs.length && !legacyArchives.length) return;
+
+  const drop: string[] = [...legacyThumbs];
+  for (const key of legacyArchives) {
+    const data = await idb.get(key);
+    drop.push(key);
+    if (data && typeof data === 'object' && 'posts' in data && !(data as CacheData).isLocal) {
+      // Server archives keep working: their URLs are plain HTTP paths.
+      await setCachedArchive({ ...(data as CacheData), name: key });
+    }
+  }
+  await idb.delMany(drop);
+  console.log(`[Cache] Migrated legacy cache: dropped ${drop.length} stale keys.`);
+};
+
+/**
+ * Rebuild a server archive's media URLs, which are stable HTTP paths.
+ *
+ * `path` is relative to the archives root and already carries the source
+ * directory (which may be a sidecar such as `story - user`), so it is not
+ * prefixed with the archive name. Entries cached before `path` existed fall
+ * back to their stored URL.
+ */
+const rehydrateRemote = (posts: Post[]): Post[] =>
+  posts.map(post => {
+    const media = post.media.map(m => ({
+      ...m,
+      url: m.path ? `/archives/${encodeURI(m.path)}` : m.url,
+    }));
+    return { ...post, media, thumbnail: media[0]?.url ?? post.thumbnail };
+  });
+
+/**
+ * Rebuild a local archive's media URLs from a live directory handle, minting
+ * fresh blob: URLs for the paths recorded at scan time.
+ *
+ * Returns null when the folder is no longer reachable (permission declined, or
+ * the handle no longer resolves), signalling the caller to re-prompt.
+ */
+const rehydrateLocal = async (
+  posts: Post[],
+  handle: DirectoryHandle,
+  onUrl: (url: string) => void,
+): Promise<Post[] | null> => {
+  if (!(await ensureReadPermission(handle))) return null;
+
+  let files: LocalArchiveFile[];
+  try {
+    files = await filesFromDirectory(handle);
+  } catch (err) {
+    console.warn('[Cache] Directory handle no longer readable:', err);
+    return null;
+  }
+
+  const byPath = new Map(files.map(f => [f.webkitRelativePath, f]));
+
+  return posts.map(post => {
+    const media = post.media.map(m => {
+      const file = byPath.get(m.path);
+      if (!file) return { ...m, url: '' };
+      const url = file.createObjectUrl(m.type === 'video' ? 'video/mp4' : 'image/jpeg');
+      onUrl(url);
+      return { ...m, url };
+    });
+    return { ...post, media, thumbnail: media[0]?.url ?? '' };
+  });
+};
+
+export interface RestoredArchive {
+  posts: Post[];
+  stories: Post[];
+  highlights: Post[];
+  profileMetadata: CacheData['profileMetadata'];
+}
+
+/**
+ * Turn a cache entry back into displayable state.
+ *
+ * `onUrl` receives every blob: URL minted so the caller can revoke them later.
+ * Returns null if a local archive's folder can no longer be reached.
+ */
+export const restoreArchive = async (
+  data: CacheData,
+  onUrl: (url: string) => void,
+): Promise<RestoredArchive | null> => {
+  if (!data.isLocal) {
+    return {
+      posts: rehydrateRemote(data.posts),
+      stories: rehydrateRemote(data.stories),
+      highlights: rehydrateRemote(data.highlights ?? []),
+      profileMetadata: data.profileMetadata,
+    };
+  }
+
+  const handle = await getDirectoryHandle(data.name);
+  if (!handle) return null;
+
+  const posts = await rehydrateLocal(data.posts, handle, onUrl);
+  if (!posts) return null;
+  const stories = (await rehydrateLocal(data.stories, handle, onUrl)) ?? [];
+  const highlights = (await rehydrateLocal(data.highlights ?? [], handle, onUrl)) ?? [];
+
+  return { posts, stories, highlights, profileMetadata: data.profileMetadata };
+};

src/lib/archive-files.ts

@@ -0,0 +1,60 @@
+import { ArchiveFile, ArchiveSource } from '../types';
+
+export class LocalArchiveFile implements ArchiveFile {
+  /** Blob URLs minted here are revocable and must be released when done. */
+  readonly revocable = true;
+
+  /**
+   * @param explicitPath Set when the file came from the File System Access API,
+   *   whose File objects carry an empty webkitRelativePath.
+   */
+  constructor(private file: File, private explicitPath?: string) {}
+  get name() { return this.file.name; }
+  get webkitRelativePath() { return this.explicitPath ?? this.file.webkitRelativePath; }
+  get size() { return this.file.size; }
+  text() { return this.file.text(); }
+  arrayBuffer() { return this.file.arrayBuffer(); }
+
+  /**
+   * A blob: URL backed directly by the on-disk File.
+   *
+   * Deliberately does NOT go through arrayBuffer() — a File is already a Blob,
+   * so this hands the browser a disk-backed handle instead of pulling the whole
+   * file into memory. Doing otherwise means a 20GB archive tries to become 20GB
+   * of resident blobs.
+   *
+   * When the picker gave us no MIME type, slice() re-tags the blob with a hint.
+   * slice() is a zero-copy view, so this stays memory-free either way.
+   */
+  createObjectUrl(mimeHint?: string) {
+    const source = this.file.type || !mimeHint
+      ? this.file
+      : this.file.slice(0, this.file.size, mimeHint);
+    return URL.createObjectURL(source);
+  }
+}
+
+export class RemoteArchiveFile implements ArchiveFile {
+  /** Served over HTTP; there is no object URL to release. */
+  readonly revocable = false;
+
+  constructor(
+    public name: string,
+    public webkitRelativePath: string,
+    public size: number,
+    public url: string,
+    public source?: ArchiveSource,
+    public mtime?: number
+  ) {}
+  async text() {
+    const res = await fetch(this.url);
+    return res.text();
+  }
+  async arrayBuffer() {
+    const res = await fetch(this.url);
+    return res.arrayBuffer();
+  }
+  createObjectUrl() {
+    return this.url;
+  }
+}

src/lib/archive-grouping.test.ts

@@ -0,0 +1,89 @@
+import { describe, expect, it } from 'vitest';
+import { classifyDirectory, groupArchiveDirectories } from './archive-grouping';
+
+describe('classifyDirectory', () => {
+  it('treats a bare profile directory as the base', () => {
+    expect(classifyDirectory('4utumn07')).toEqual({
+      owner: '4utumn07',
+      source: { kind: 'posts', dir: '4utumn07' },
+    });
+  });
+
+  it('recognises a reels sidecar', () => {
+    expect(classifyDirectory('4utumn07 - reels')).toEqual({
+      owner: '4utumn07',
+      source: { kind: 'reels', dir: '4utumn07 - reels' },
+    });
+  });
+
+  it('recognises a stories sidecar', () => {
+    expect(classifyDirectory('story - dawn_petal')).toEqual({
+      owner: 'dawn_petal',
+      source: { kind: 'stories', dir: 'story - dawn_petal' },
+    });
+  });
+
+  it('splits highlight owner from title', () => {
+    const { owner, source } = classifyDirectory('story highlights - 4utumn07 - Sunstory');
+    expect(owner).toBe('4utumn07');
+    expect(source.kind).toBe('highlight');
+    expect(source.title).toBe('Sunstory');
+  });
+
+  it.each([
+    ['story highlights - theoldlyricmuseinsta - 💙1999-2005 era', 'theoldlyricmuseinsta', '💙1999-2005 era'],
+    ['story highlights - member_theworld - [Bracket]', 'member_theworld', '[Bracket]'],
+    ['story highlights - official_band - Tour Schedule', 'official_band', 'Tour Schedule'],
+    ['story highlights - 4utumn07 - Sketching⠀', '4utumn07', 'Sketching⠀'],
+    ['story highlights - official_band - A.B.C', 'official_band', 'A.B.C'],
+  ])('handles real-world title %s', (dir, owner, title) => {
+    const result = classifyDirectory(dir);
+    expect(result.owner).toBe(owner);
+    expect(result.source.title).toBe(title);
+  });
+
+  it('keeps titles containing " - " intact', () => {
+    // The username is matched as a non-space run, so only the first separator
+    // splits owner from title.
+    const { owner, source } = classifyDirectory('story highlights - user - a - b');
+    expect(owner).toBe('user');
+    expect(source.title).toBe('a - b');
+  });
+
+  it('does not mistake a profile with spaces for a sidecar', () => {
+    expect(classifyDirectory('Heejin_Bubble heejinmedia').source.kind).toBe('posts');
+  });
+});
+
+describe('groupArchiveDirectories', () => {
+  const dirs = [
+    '4utumn07',
+    '4utumn07 - reels',
+    'story - 4utumn07',
+    'story highlights - 4utumn07 - Sunstory',
+    'story highlights - 4utumn07 - Sketching⠀',
+    'kestrelsings',
+  ];
+
+  it('folds sidecars into their base profile', () => {
+    const groups = groupArchiveDirectories(dirs);
+    expect([...groups.keys()].sort()).toEqual(['4utumn07', 'kestrelsings']);
+    expect(groups.get('4utumn07')).toHaveLength(5);
+    expect(groups.get('kestrelsings')).toHaveLength(1);
+  });
+
+  it('orders sources posts, reels, stories, then highlights by title', () => {
+    const sources = groupArchiveDirectories(dirs).get('4utumn07')!;
+    expect(sources.map(s => s.kind)).toEqual(['posts', 'reels', 'stories', 'highlight', 'highlight']);
+    expect(sources.slice(3).map(s => s.title)).toEqual(['Sketching⠀', 'Sunstory']);
+  });
+
+  it('still groups a sidecar whose base profile is missing', () => {
+    const groups = groupArchiveDirectories(['story - orphan']);
+    expect(groups.get('orphan')).toEqual([{ kind: 'stories', dir: 'story - orphan' }]);
+  });
+
+  it('is stable for an empty archive root', () => {
+    expect(groupArchiveDirectories([]).size).toBe(0);
+  });
+});

src/lib/archive-grouping.ts

@@ -0,0 +1,71 @@
+/**
+ * Archive directory naming rules.
+ *
+ * Shared by the server (to fold sidecar directories into one profile) and the
+ * test suite. Kept free of Node built-ins so it can be imported from either.
+ */
+
+export type SourceKind = 'posts' | 'reels' | 'stories' | 'highlight';
+
+export interface ArchiveSource {
+  kind: SourceKind;
+  /** Directory name relative to the archives root. */
+  dir: string;
+  /** Highlight title, for kind === 'highlight'. */
+  title?: string;
+}
+
+/**
+ * Sidecar directories sit next to the profile directory they belong to:
+ *
+ *   4utumn07                                 -> posts     (base)
+ *   4utumn07 - reels                         -> reels
+ *   story - 4utumn07                         -> stories
+ *   story highlights - 4utumn07 - Sunstory   -> highlight "Sunstory"
+ *
+ * Instagram usernames cannot contain spaces, so matching the username as a
+ * run of non-space characters reliably separates it from a highlight title
+ * (titles may themselves contain spaces, dashes and emoji).
+ */
+export const classifyDirectory = (dirName: string): { owner: string; source: ArchiveSource } => {
+  const highlight = /^story highlights - ([^ ]+) - (.+)$/.exec(dirName);
+  if (highlight) {
+    return { owner: highlight[1], source: { kind: 'highlight', dir: dirName, title: highlight[2] } };
+  }
+
+  const stories = /^story - ([^ ]+)$/.exec(dirName);
+  if (stories) {
+    return { owner: stories[1], source: { kind: 'stories', dir: dirName } };
+  }
+
+  const reels = /^([^ ]+) - reels$/.exec(dirName);
+  if (reels) {
+    return { owner: reels[1], source: { kind: 'reels', dir: dirName } };
+  }
+
+  return { owner: dirName, source: { kind: 'posts', dir: dirName } };
+};
+
+const RANK: Record<SourceKind, number> = { posts: 0, reels: 1, stories: 2, highlight: 3 };
+
+/**
+ * Group the archive root's directories by profile.
+ *
+ * A sidecar whose owner has no base directory still forms a group of its own,
+ * so nothing becomes invisible just because the base profile is missing.
+ */
+export const groupArchiveDirectories = (dirNames: string[]): Map<string, ArchiveSource[]> => {
+  const groups = new Map<string, ArchiveSource[]>();
+
+  for (const dirName of dirNames) {
+    const { owner, source } = classifyDirectory(dirName);
+    if (!groups.has(owner)) groups.set(owner, []);
+    groups.get(owner)!.push(source);
+  }
+
+  for (const sources of groups.values()) {
+    sources.sort((a, b) => RANK[a.kind] - RANK[b.kind] || (a.title ?? '').localeCompare(b.title ?? ''));
+  }
+
+  return groups;
+};

src/lib/archive-index.test.ts

@@ -0,0 +1,34 @@
+import { describe, expect, it } from 'vitest';
+import { isSystemDirectory } from './archive-index';
+
+describe('isSystemDirectory', () => {
+  it.each([
+    ['@eaDir', 'Synology thumbnail/index metadata, written inside every folder'],
+    ['@tmp', 'Synology scratch'],
+    ['.sync', 'Resilio state'],
+    ['.DS_Store', 'macOS'],
+    ['#recycle', 'Synology deletions'],
+    ['#snapshot', 'Synology snapshots'],
+  ])('skips %s (%s)', name => {
+    expect(isSystemDirectory(name)).toBe(true);
+  });
+
+  it.each([
+    '4utumn07',
+    '4utumn07 - reels',
+    'story - dawn_petal',
+    'story highlights - official_band - A.B.C',
+    'story highlights - theoldlyricmuseinsta - 💙1999-2005 era',
+    'Heejin_Bubble heejinmedia',
+    'gallery-dl',
+    'posts',
+  ])('keeps %s', name => {
+    expect(isSystemDirectory(name)).toBe(false);
+  });
+
+  it('does not treat a leading underscore as a system directory', () => {
+    // `_gemini-plans` is filtered separately at the archive root only; nothing
+    // below the root should be excluded just for starting with an underscore.
+    expect(isSystemDirectory('_gemini-plans')).toBe(false);
+  });
+});

src/lib/archive-index.ts

@@ -0,0 +1,248 @@
+import fs from 'fs';
+import fsp from 'fs/promises';
+import path from 'path';
+import { ArchiveSource, SourceKind, groupArchiveDirectories } from './archive-grouping.js';
+
+/**
+ * On-disk archive index.
+ *
+ * Archives live on network storage where per-file `stat` costs ~1.4ms and does
+ * not parallelise well, so walking every file on each request is unaffordable:
+ * measured against a real 110k-file archive root, listing took ~52s.
+ *
+ * Directory `stat` is effectively free, so each source directory is indexed
+ * once and re-used until its mtime changes. The index is warmed in the
+ * background at startup and persisted, making steady-state requests instant.
+ */
+
+export interface IndexedFile {
+  path: string;
+  size: number;
+  mtime: number;
+  kind: SourceKind;
+  title?: string;
+}
+
+interface DirIndex {
+  dir: string;
+  /** Directory mtime the index was built from; the cache key. */
+  mtimeMs: number;
+  files: IndexedFile[];
+}
+
+const MEDIA_RE = /\.(jpg|jpeg|png|webp|gif|bmp|tiff|mp4|webm|ogv|mov)$/i;
+const STAT_CONCURRENCY = 16;
+
+/**
+ * Directories the walk must never descend into.
+ *
+ * NAS filesystems scatter sidecar metadata *inside* every folder, not just at
+ * the share root: Synology writes `@eaDir` (thumbnails and indexing data),
+ * `#recycle` holds deletions, and `.sync` is Resilio's state. Indexing those
+ * would count NAS thumbnails as archive media and spend a stat on each one —
+ * measured on a real share, `@eaDir` accounted for 12,516 of 123,023 files.
+ *
+ * The archive root is already filtered by prefix; this is the same rule applied
+ * at every level below it.
+ */
+export const isSystemDirectory = (name: string): boolean =>
+  name.startsWith('@') || name.startsWith('.') || name === '#recycle' || name === '#snapshot';
+
+export class ArchiveIndex {
+  private dirs = new Map<string, DirIndex>();
+  private inFlight = new Map<string, Promise<DirIndex>>();
+  private dirty = false;
+
+  constructor(private archivesDir: string, private cachePath: string) {}
+
+  /** Visible (non-system) directories at the archive root. */
+  private listRootDirs(): string[] {
+    return fs.readdirSync(this.archivesDir, { withFileTypes: true })
+      .filter(e => e.isDirectory() && !isSystemDirectory(e.name) && !e.name.startsWith('_'))
+      .map(e => e.name);
+  }
+
+  groups(): Map<string, ArchiveSource[]> {
+    return groupArchiveDirectories(this.listRootDirs());
+  }
+
+  private dirMtime(dir: string): number {
+    try {
+      return fs.statSync(path.join(this.archivesDir, dir)).mtimeMs;
+    } catch {
+      return 0;
+    }
+  }
+
+  /** Recursively list relative file paths without stat()ing them. */
+  private walk(absDir: string, base = ''): string[] {
+    let out: string[] = [];
+    let entries: fs.Dirent[];
+    try {
+      entries = fs.readdirSync(absDir, { withFileTypes: true });
+    } catch {
+      return out;
+    }
+    for (const entry of entries) {
+      if (isSystemDirectory(entry.name)) continue;
+      const rel = base ? `${base}/${entry.name}` : entry.name;
+      if (entry.isDirectory()) out = out.concat(this.walk(path.join(absDir, entry.name), rel));
+      else if (entry.isFile()) out.push(rel);
+    }
+    return out;
+  }
+
+  private async buildDir(source: ArchiveSource): Promise<DirIndex> {
+    const started = Date.now();
+    const mtimeMs = this.dirMtime(source.dir);
+    const absDir = path.join(this.archivesDir, source.dir);
+    const relPaths = this.walk(absDir);
+
+    // Only media needs a size (the client thumbnails anything over 1MiB), and
+    // only highlights need an mtime (their filenames carry no date). Skipping
+    // the rest avoids thousands of pointless round trips.
+    const needsStat = (rel: string) => MEDIA_RE.test(rel) || source.kind === 'highlight';
+
+    const files: IndexedFile[] = relPaths.map(rel => ({
+      path: `${source.dir}/${rel}`,
+      size: 0,
+      mtime: 0,
+      kind: source.kind,
+      ...(source.title ? { title: source.title } : {}),
+    }));
+
+    const targets = files.filter((_, i) => needsStat(relPaths[i]));
+    let cursor = 0;
+    const worker = async () => {
+      while (cursor < targets.length) {
+        const file = targets[cursor++];
+        try {
+          const stat = await fsp.stat(path.join(this.archivesDir, file.path));
+          file.size = stat.size;
+          file.mtime = stat.mtimeMs;
+        } catch { /* raced with a delete */ }
+      }
+    };
+    await Promise.all(Array.from({ length: STAT_CONCURRENCY }, worker));
+
+    console.log(
+      `[Index] ${source.dir}: ${files.length} files (${targets.length} statted) in ${((Date.now() - started) / 1000).toFixed(1)}s`
+    );
+    this.dirty = true;
+    return { dir: source.dir, mtimeMs, files };
+  }
+
+  /** Index for one source directory, rebuilding only if its mtime moved. */
+  private async ensureDir(source: ArchiveSource): Promise<DirIndex> {
+    const cached = this.dirs.get(source.dir);
+    const mtimeMs = this.dirMtime(source.dir);
+    if (cached && cached.mtimeMs === mtimeMs) return cached;
+
+    // Collapse concurrent requests for the same directory into one walk.
+    const existing = this.inFlight.get(source.dir);
+    if (existing) return existing;
+
+    const build = this.buildDir(source).then(index => {
+      this.dirs.set(source.dir, index);
+      this.inFlight.delete(source.dir);
+      return index;
+    }).catch(err => {
+      this.inFlight.delete(source.dir);
+      throw err;
+    });
+    this.inFlight.set(source.dir, build);
+    return build;
+  }
+
+  /** All files for one profile, across its base and sidecar directories. */
+  async filesFor(owner: string): Promise<IndexedFile[] | null> {
+    const sources = this.groups().get(owner);
+    if (!sources?.length) return null;
+    const indexes = await Promise.all(sources.map(s => this.ensureDir(s)));
+    return indexes.flatMap(i => i.files);
+  }
+
+  /**
+   * A cheap change signature for a profile, used by the client to decide
+   * whether its cached copy is stale. Built from directory mtimes only, so it
+   * costs one stat per source directory rather than a full walk.
+   */
+  signatureFor(sources: ArchiveSource[]): string {
+    return sources.map(s => `${s.dir}:${this.dirMtime(s.dir)}`).join('|');
+  }
+
+  /** File count for a profile, if its directories are already indexed. */
+  countFor(sources: ArchiveSource[]): number | null {
+    let total = 0;
+    for (const source of sources) {
+      const cached = this.dirs.get(source.dir);
+      if (!cached) return null;
+      total += cached.files.length;
+    }
+    return total;
+  }
+
+  /**
+   * Best-effort profile picture.
+   *
+   * Probes the conventional filenames first (one stat each) and only falls back
+   * to the indexed listing, so an unindexed archive still gets a thumbnail
+   * without triggering a walk.
+   */
+  thumbnailFor(owner: string, sources: ArchiveSource[]): string {
+    const base = sources.find(s => s.kind === 'posts') ?? sources[0];
+    if (!base) return '';
+
+    for (const candidate of [`${owner}.jpg`, `${owner}_profile_pic.jpg`, `${owner}.jpeg`, `${owner}.png`]) {
+      if (fs.existsSync(path.join(this.archivesDir, base.dir, candidate))) {
+        return `/archives/${encodeURI(`${base.dir}/${candidate}`)}`;
+      }
+    }
+
+    const cached = this.dirs.get(base.dir);
+    if (cached) {
+      const pick = cached.files.find(f => /_profile_pic\.jpg$/i.test(f.path))
+        ?? cached.files.find(f => /\.(jpg|jpeg|png|webp)$/i.test(f.path));
+      if (pick) return `/archives/${encodeURI(pick.path)}`;
+    }
+    return '';
+  }
+
+  /** Walk every directory once, in the background, so first opens are fast. */
+  async warm(): Promise<void> {
+    const started = Date.now();
+    const sources = [...this.groups().values()].flat();
+    console.log(`[Index] Warming ${sources.length} source directories...`);
+    for (const source of sources) {
+      try {
+        await this.ensureDir(source);
+      } catch (err) {
+        console.error(`[Index] Failed to index ${source.dir}:`, err);
+      }
+    }
+    await this.save();
+    console.log(`[Index] Warm complete in ${((Date.now() - started) / 1000).toFixed(1)}s`);
+  }
+
+  async load(): Promise<void> {
+    try {
+      const raw = await fsp.readFile(this.cachePath, 'utf8');
+      const parsed: DirIndex[] = JSON.parse(raw);
+      for (const entry of parsed) this.dirs.set(entry.dir, entry);
+      console.log(`[Index] Loaded ${this.dirs.size} directories from ${this.cachePath}`);
+    } catch {
+      console.log('[Index] No usable index cache; will build from scratch.');
+    }
+  }
+
+  async save(): Promise<void> {
+    if (!this.dirty) return;
+    try {
+      await fsp.writeFile(this.cachePath, JSON.stringify([...this.dirs.values()]), 'utf8');
+      this.dirty = false;
+      console.log(`[Index] Persisted ${this.dirs.size} directories to ${this.cachePath}`);
+    } catch (err) {
+      console.warn('[Index] Could not persist index (continuing in memory):', err);
+    }
+  }
+}

src/lib/archive-patterns.test.ts

@@ -0,0 +1,118 @@
+import { describe, expect, it } from 'vitest';
+import { parseArchiveFilename, scopedPostId } from './archive-patterns';
+
+describe('parseArchiveFilename — Instagram export format', () => {
+  it('parses a single-image post', () => {
+    expect(parseArchiveFilename('2023-04-19_4utumn07 - CrORBIcJJbM.mp4')).toEqual({
+      postId: 'CrORBIcJJbM',
+      date: '2023-04-19',
+      username: '4utumn07',
+      index: 1,
+      ext: 'mp4',
+      isStory: false,
+    });
+  });
+
+  it('parses a carousel slide index', () => {
+    const parsed = parseArchiveFilename('2023-04-12_4utumn07 - Cq8LrxSJAJE - 3.jpg');
+    expect(parsed).toMatchObject({ postId: 'Cq8LrxSJAJE', index: 3, ext: 'jpg' });
+  });
+
+  it('groups a carousel under one post id', () => {
+    const ids = ['1', '2', '3'].map(
+      n => parseArchiveFilename(`2023-04-12_user - Cq8LrxSJAJE - ${n}.jpg`)!.postId,
+    );
+    expect(new Set(ids).size).toBe(1);
+  });
+
+  it('parses caption sidecar files', () => {
+    expect(parseArchiveFilename('2023-04-12_4utumn07 - Cq8LrxSJAJE.txt')).toMatchObject({
+      postId: 'Cq8LrxSJAJE',
+      ext: 'txt',
+    });
+  });
+
+  it('flags an explicit story suffix', () => {
+    expect(parseArchiveFilename('2023-04-12_user - ABC - story.jpg')?.isStory).toBe(true);
+  });
+
+  it('parses the story sidecar layout (date_user - N - shortcode)', () => {
+    // Files in `story - <user>` carry a per-day ordinal before the shortcode.
+    const parsed = parseArchiveFilename('2025-10-26_4utumn07 - 2 - DQRuDx9iW5Q.jpg', 'stories');
+    expect(parsed).toMatchObject({ date: '2025-10-26', username: '4utumn07', ext: 'jpg' });
+    expect(parsed!.postId).toContain('DQRuDx9iW5Q');
+  });
+
+  it('gives each story item a distinct id', () => {
+    const a = parseArchiveFilename('2026-08-13_u - 1 - Db-UTJcCUUr.mp4', 'stories')!.postId;
+    const b = parseArchiveFilename('2026-08-13_u - 2 - Db-oNJ1CWQ4.mp4', 'stories')!.postId;
+    expect(a).not.toBe(b);
+  });
+});
+
+describe('parseArchiveFilename — Instaloader format', () => {
+  it('parses a timestamped filename', () => {
+    expect(parseArchiveFilename('2024-01-01_12-00-00_UTC.jpg')).toMatchObject({
+      postId: '2024-01-01_12-00-00_UTC',
+      date: '2024-01-01',
+      index: 1,
+    });
+  });
+
+  it('parses the carousel suffix', () => {
+    expect(parseArchiveFilename('2024-01-01_12-00-00_UTC_2.jpg')?.index).toBe(2);
+  });
+
+  it('flags the story suffix', () => {
+    expect(parseArchiveFilename('2024-01-01_12-00-00_UTC_story.jpg')?.isStory).toBe(true);
+  });
+});
+
+describe('parseArchiveFilename — story highlights', () => {
+  it('parses the dateless highlight layout', () => {
+    expect(parseArchiveFilename('4utumn07 - C5dQPEYpd9W.mp4', 'highlight')).toMatchObject({
+      postId: 'C5dQPEYpd9W',
+      username: '4utumn07',
+      ext: 'mp4',
+      isStory: false,
+    });
+  });
+
+  it('dates a highlight from mtime when the filename has none', () => {
+    const mtime = Date.UTC(2024, 4, 17, 12, 0, 0);
+    expect(parseArchiveFilename('user - ABC.jpg', 'highlight', mtime)?.date).toBe('2024-05-17');
+  });
+
+  it('leaves the date empty when no mtime is available', () => {
+    expect(parseArchiveFilename('user - ABC.jpg', 'highlight')?.date).toBe('');
+  });
+
+  it('does not apply the loose highlight pattern outside highlight directories', () => {
+    // Would otherwise swallow ordinary "a - b.jpg" filenames.
+    expect(parseArchiveFilename('user - ABC.jpg', 'posts')).toBeNull();
+  });
+});
+
+describe('parseArchiveFilename — non-matching files', () => {
+  it.each(['4utumn07.jpg', 'profile_pic.jpg', 'README.md', 'no-separator.png'])(
+    'returns null for %s',
+    name => expect(parseArchiveFilename(name)).toBeNull(),
+  );
+});
+
+describe('scopedPostId', () => {
+  it('leaves base-profile ids untouched so permalinks keep working', () => {
+    expect(scopedPostId('Cq8LrxSJAJE', 'posts')).toBe('Cq8LrxSJAJE');
+  });
+
+  it('namespaces sidecar ids by directory', () => {
+    expect(scopedPostId('C5dQ', 'highlight', 'story highlights - u - Sunstory'))
+      .toBe('story highlights - u - Sunstory/C5dQ');
+  });
+
+  it('keeps the same shortcode distinct across sources', () => {
+    const inPosts = scopedPostId('ABC', 'posts');
+    const inHighlight = scopedPostId('ABC', 'highlight', 'story highlights - u - H');
+    expect(inPosts).not.toBe(inHighlight);
+  });
+});

src/lib/archive-patterns.ts

@@ -0,0 +1,99 @@
+import { SourceKind } from '../types';
+
+/**
+ * Filename parsing rules for the archive formats the viewer understands.
+ *
+ * Kept as pure functions so the riskiest part of the scanner — deriving post
+ * identity, date and carousel order from a filename — can be tested directly.
+ */
+
+/** Instagram export: `2023-04-12_user - Cq8LrxSJAJE - 2.jpg` */
+export const EXPORT_RE = /^(\d{4}-\d{2}-\d{2})_(.+?) - (.+?)(?: - (\d+))?(?: - (story))?\.(.+)$/;
+
+/** Instaloader: `2024-01-01_12-00-00_UTC_2.jpg` */
+export const INSTALOADER_RE = /^(\d{4}-\d{2}-\d{2}_\d{2}-\d{2}-\d{2}_UTC)(?:_(\d+))?(?:_(story))?\.(.+)$/;
+
+/**
+ * Story highlight: `user - C5dQPEYpd9W.mp4` — no date prefix.
+ *
+ * Loose enough to match ordinary filenames, so it is only applied to files the
+ * server has already tagged as coming from a highlight directory.
+ */
+export const HIGHLIGHT_RE = /^(.+?) - ([A-Za-z0-9_-]+)\.(\w+)$/;
+
+export interface ParsedFilename {
+  postId: string;
+  /** ISO date (YYYY-MM-DD), or '' when the filename carries none. */
+  date: string;
+  username: string;
+  /** 1-based carousel position. */
+  index: number;
+  ext: string;
+  isStory: boolean;
+}
+
+/**
+ * Parse an archive filename into post identity.
+ *
+ * `kind` selects which patterns apply; `mtime` supplies a date for formats that
+ * have none (highlights), so those items still sort and render sensibly.
+ * Returns null when no pattern matches — e.g. a profile picture.
+ */
+export const parseArchiveFilename = (
+  fileName: string,
+  kind: SourceKind = 'posts',
+  mtime?: number,
+): ParsedFilename | null => {
+  const exp = EXPORT_RE.exec(fileName);
+  if (exp) {
+    const [, date, username, postId, indexStr, story, ext] = exp;
+    return {
+      postId,
+      date,
+      username,
+      index: indexStr ? parseInt(indexStr, 10) : 1,
+      ext,
+      isStory: Boolean(story),
+    };
+  }
+
+  const ins = INSTALOADER_RE.exec(fileName);
+  if (ins) {
+    const [, postId, indexStr, story, ext] = ins;
+    return {
+      postId,
+      date: postId.split('_')[0],
+      username: '',
+      index: indexStr ? parseInt(indexStr, 10) : 1,
+      ext,
+      isStory: Boolean(story),
+    };
+  }
+
+  if (kind === 'highlight') {
+    const hl = HIGHLIGHT_RE.exec(fileName);
+    if (hl) {
+      const [, username, shortcode, ext] = hl;
+      return {
+        postId: shortcode,
+        date: mtime ? new Date(mtime).toISOString().split('T')[0] : '',
+        username,
+        index: 1,
+        ext,
+        isStory: false,
+      };
+    }
+  }
+
+  return null;
+};
+
+/**
+ * Namespace a post ID by its source directory.
+ *
+ * Base-profile IDs are left untouched so existing permalinks keep working;
+ * sidecar IDs are prefixed so a shortcode appearing in both the profile and a
+ * highlight stays two distinct posts.
+ */
+export const scopedPostId = (postId: string, kind: SourceKind, dir?: string): string =>
+  kind === 'posts' ? postId : `${dir ?? kind}/${postId}`;

src/lib/directory-handle.ts

@@ -0,0 +1,86 @@
+import { LocalArchiveFile } from './archive-files';
+
+/**
+ * File System Access API helpers.
+ *
+ * A `blob:` URL dies with the document, so a cached local archive whose media
+ * URLs are blob: URLs is worthless after a reload. A FileSystemDirectoryHandle,
+ * by contrast, is structured-cloneable and survives in IndexedDB — so we can
+ * re-open the same folder on a return visit and mint fresh URLs from it.
+ *
+ * Only Chromium implements showDirectoryPicker today; callers must handle the
+ * unsupported case by falling back to the <input webkitdirectory> flow.
+ */
+
+// Minimal typings — TS's lib.dom does not ship these in the configured version.
+type PermissionState = 'granted' | 'denied' | 'prompt';
+interface FileSystemHandlePermissionDescriptor { mode?: 'read' | 'readwrite' }
+export interface DirectoryHandle {
+  name: string;
+  kind: 'directory';
+  values(): AsyncIterableIterator<DirectoryHandle | FileHandle>;
+  queryPermission?(d?: FileSystemHandlePermissionDescriptor): Promise<PermissionState>;
+  requestPermission?(d?: FileSystemHandlePermissionDescriptor): Promise<PermissionState>;
+}
+interface FileHandle {
+  name: string;
+  kind: 'file';
+  getFile(): Promise<File>;
+}
+
+export const isDirectoryPickerSupported = () =>
+  typeof window !== 'undefined' && 'showDirectoryPicker' in window;
+
+export const pickDirectory = async (): Promise<DirectoryHandle | null> => {
+  if (!isDirectoryPickerSupported()) return null;
+  try {
+    return await (window as any).showDirectoryPicker({ mode: 'read' });
+  } catch (err) {
+    // AbortError simply means the user dismissed the picker.
+    return null;
+  }
+};
+
+/**
+ * Confirm we may still read this handle. Returns false when the user declines
+ * or the grant has lapsed, in which case the caller should re-prompt.
+ *
+ * `requestPermission` must be called from a user gesture, so only call this
+ * while handling a click.
+ */
+export const ensureReadPermission = async (handle: DirectoryHandle): Promise<boolean> => {
+  try {
+    if (!handle.queryPermission) return true;
+    if ((await handle.queryPermission({ mode: 'read' })) === 'granted') return true;
+    if (!handle.requestPermission) return false;
+    return (await handle.requestPermission({ mode: 'read' })) === 'granted';
+  } catch {
+    return false;
+  }
+};
+
+/**
+ * Recursively collect every file in the directory.
+ *
+ * Paths are prefixed with the root directory's name so they line up with the
+ * `webkitRelativePath` values produced by <input webkitdirectory>, keeping
+ * cached media paths valid regardless of which picker created them.
+ */
+export const filesFromDirectory = async (handle: DirectoryHandle): Promise<LocalArchiveFile[]> => {
+  const out: LocalArchiveFile[] = [];
+
+  const walk = async (dir: DirectoryHandle, prefix: string) => {
+    for await (const entry of dir.values()) {
+      const entryPath = `${prefix}/${entry.name}`;
+      if (entry.kind === 'directory') {
+        await walk(entry as DirectoryHandle, entryPath);
+      } else {
+        const file = await (entry as FileHandle).getFile();
+        out.push(new LocalArchiveFile(file, entryPath));
+      }
+    }
+  };
+
+  await walk(handle, handle.name);
+  return out;
+};

src/lib/motion.ts

@@ -0,0 +1,44 @@
+import type { Transition } from 'motion/react';
+
+/**
+ * Shared motion vocabulary, tuned to feel like a native iOS app.
+ *
+ * Two rules do most of the work:
+ *  - UIKit animates with springs, not fixed-duration easing, so gestures hand
+ *    their exit velocity to the animation and motion continues rather than
+ *    restarting.
+ *  - iOS springs are critically damped. They settle firmly with no visible
+ *    bounce; overshoot reads as "web animation", not "native".
+ */
+
+/** The curve UIKit uses for sheet presentation. */
+export const IOS_EASE = [0.32, 0.72, 0, 1] as const;
+
+/** Moving between peers: carousel slides, next/previous post. */
+export const NAVIGATE: Transition = { type: 'spring', stiffness: 420, damping: 40, mass: 1 };
+
+/** Presenting or dismissing a surface. Slightly softer than navigation. */
+export const PRESENT: Transition = { type: 'spring', stiffness: 320, damping: 34, mass: 1 };
+
+/** Backdrops and cross-fades, where a spring would feel fussy. */
+export const FADE: Transition = { duration: 0.28, ease: IOS_EASE };
+
+/** Touch-down feedback. Fast enough to feel like a direct response. */
+export const PRESS: Transition = { type: 'spring', stiffness: 600, damping: 30 };
+
+/**
+ * Continue a drag into its animation.
+ *
+ * Handing the gesture's exit velocity to the spring is what separates "the
+ * sheet kept moving because I flicked it" from "the sheet started a new
+ * animation once I let go".
+ */
+export const withVelocity = (velocity: number, base: Transition = NAVIGATE): Transition => ({
+  ...base,
+  velocity,
+});
+
+/** True when the viewer has asked the OS to reduce motion. */
+export const prefersReducedMotion = () =>
+  typeof window !== 'undefined' &&
+  window.matchMedia('(prefers-reduced-motion: reduce)').matches;

src/lib/post-tabs.test.ts

@@ -0,0 +1,100 @@
+import { describe, expect, it } from 'vitest';
+import { dedupePostCopies, hasReelSource, makeIsReel, postsForTab } from './post-tabs';
+import { MediaFile, Post } from '../types';
+
+const media = (type: MediaFile['type'], index = 1): MediaFile => ({
+  name: `f${index}.${type === 'video' ? 'mp4' : 'jpg'}`,
+  path: `d/f${index}`, url: '', type, index,
+});
+
+const post = (id: string, opts: Partial<Post> = {}): Post => ({
+  id, date: '2024-01-01', username: 'u', caption: '', media: [media('image')], thumbnail: '', ...opts,
+});
+
+const video = (id: string, opts: Partial<Post> = {}) => post(id, { media: [media('video')], ...opts });
+const carousel = (id: string, opts: Partial<Post> = {}) =>
+  post(id, { media: [media('image', 1), media('video', 2)], ...opts });
+
+describe('hasReelSource', () => {
+  it('is false for an archive with no reels directory', () => {
+    expect(hasReelSource([post('A'), video('B')])).toBe(false);
+  });
+
+  it('is true once any post came from a reels directory', () => {
+    expect(hasReelSource([post('A'), video('u - reels/B', { source: 'reels' })])).toBe(true);
+  });
+});
+
+describe('makeIsReel', () => {
+  it('believes the reels directory when there is one', () => {
+    const posts = [video('A'), video('u - reels/B', { source: 'reels' })];
+    const isReel = makeIsReel(posts);
+    // A is a lone video too, but the archive states which posts are reels.
+    expect(isReel(posts[0])).toBe(false);
+    expect(isReel(posts[1])).toBe(true);
+  });
+
+  it('falls back to the lone-video heuristic without one', () => {
+    const posts = [post('A'), video('B'), carousel('C')];
+    const isReel = makeIsReel(posts);
+    expect(posts.map(isReel)).toEqual([false, true, false]);
+  });
+});
+
+describe('dedupePostCopies', () => {
+  it('leaves distinct posts alone', () => {
+    const posts = [post('A'), video('B')];
+    expect(dedupePostCopies(posts).map(p => p.id)).toEqual(['A', 'B']);
+  });
+
+  it('collapses a reel fetched into both the profile and the reels directory', () => {
+    const posts = [video('B'), video('u - reels/B', { source: 'reels' })];
+    const deduped = dedupePostCopies(posts);
+    expect(deduped).toHaveLength(1);
+    // The reels copy wins, so the survivor is still recognised as a reel.
+    expect(deduped[0].source).toBe('reels');
+  });
+
+  it('picks the reels copy regardless of scan order', () => {
+    const profileCopy = video('B');
+    const reelCopy = video('u - reels/B', { source: 'reels' });
+    expect(dedupePostCopies([profileCopy, reelCopy])[0].source).toBe('reels');
+    expect(dedupePostCopies([reelCopy, profileCopy])[0].source).toBe('reels');
+  });
+
+  it('keeps the position of the first copy seen', () => {
+    const posts = [post('A'), video('B'), post('C'), video('u - reels/B', { source: 'reels' })];
+    expect(dedupePostCopies(posts).map(p => p.id.split('/').pop())).toEqual(['A', 'B', 'C']);
+  });
+});
+
+describe('postsForTab', () => {
+  it('shows reels in the profile grid, as Instagram does', () => {
+    const posts = [post('A'), video('u - reels/B', { source: 'reels' })];
+    expect(postsForTab(posts, 'posts').map(p => p.id)).toEqual(['A', 'u - reels/B']);
+  });
+
+  it('shows the same reel in both tabs', () => {
+    const posts = [post('A'), video('u - reels/B', { source: 'reels' })];
+    const inGrid = postsForTab(posts, 'posts').map(p => p.id);
+    const inReels = postsForTab(posts, 'reels').map(p => p.id);
+    expect(inReels).toEqual(['u - reels/B']);
+    expect(inGrid).toContain('u - reels/B');
+  });
+
+  it('shows a duplicated reel once in the grid, not twice', () => {
+    const posts = [post('A'), video('B'), video('u - reels/B', { source: 'reels' })];
+    expect(postsForTab(posts, 'posts')).toHaveLength(2);
+    expect(postsForTab(posts, 'reels')).toHaveLength(1);
+  });
+
+  it('treats lone videos as reels for archives with no reels directory', () => {
+    const posts = [post('A'), video('B'), carousel('C')];
+    expect(postsForTab(posts, 'posts').map(p => p.id)).toEqual(['A', 'B', 'C']);
+    expect(postsForTab(posts, 'reels').map(p => p.id)).toEqual(['B']);
+  });
+
+  it('has nothing saved', () => {
+    expect(postsForTab([post('A')], 'saved')).toEqual([]);
+  });
+});

src/lib/post-tabs.ts

@@ -0,0 +1,103 @@
+import { Post, SourceKind } from '../types';
+import { Tab } from './routing';
+
+/**
+ * Which posts each profile tab shows.
+ *
+ * Instagram's profile grid holds everything the account posted — photos,
+ * carousels and reels alike — and the Reels tab is a *filtered view* of that
+ * same set rather than a separate one. So a reel belongs in both tabs, and
+ * only the Reels tab does any filtering.
+ *
+ * Kept pure and separate from App.tsx so the reel heuristic and the
+ * duplicate-copy rules can be tested directly.
+ */
+
+/**
+ * The shortcode shared by every copy of a post, regardless of which source
+ * directory it came from. Sidecar ids are directory-scoped
+ * (`4utumn07 - reels/Cq8LrxSJAJE`); the trailing segment is the shortcode.
+ */
+const shortcode = (post: Post): string => post.id.split('/').pop() ?? post.id;
+
+/**
+ * True when the archive has a `- reels` sidecar directory, i.e. it states
+ * outright which posts are reels.
+ */
+export const hasReelSource = (posts: Post[]): boolean => posts.some(p => p.source === 'reels');
+
+/**
+ * Build the reel test for an archive.
+ *
+ * Instagram's own marker is `product_type: "clips"` on the post's GraphQL
+ * node, but only Instaloader archives carry that metadata, and only on newer
+ * captures — JDownloader grabs are media plus a caption `.txt` and nothing
+ * else (see docs/jdownloader.md). So:
+ *
+ *   - archives with a `- reels` directory are believed outright;
+ *   - everything else falls back to treating a lone video as a reel.
+ *
+ * The fallback is a guess: it cannot tell a reel from an ordinary feed video
+ * or an old IGTV upload, all three of which are plain `GraphVideo` nodes
+ * distinguished only by `product_type`.
+ */
+export const makeIsReel = (posts: Post[]): ((post: Post) => boolean) => (
+  hasReelSource(posts)
+    ? (post: Post) => post.source === 'reels'
+    : (post: Post) => post.media.length === 1 && post.media[0]?.type === 'video'
+);
+
+/** Preference order when the same post was fetched into more than one directory. */
+const SOURCE_RANK: Record<SourceKind, number> = { reels: 0, posts: 1, stories: 2, highlight: 3 };
+
+const rankOf = (post: Post): number => SOURCE_RANK[post.source ?? 'posts'];
+
+/**
+ * Collapse copies of one post that were fetched into more than one directory.
+ *
+ * The JDownloader flow crawls a profile URL and its `/reels/` URL separately
+ * because the profile page misses some reels — so the two overlap, and a reel
+ * present in both lands on disk twice. Those become two posts with distinct
+ * directory-scoped ids, which the grid would happily render side by side.
+ *
+ * The reels-source copy wins, so the surviving post still reports
+ * `source: 'reels'` and both the Reels tab and `tabForSource` recognise it.
+ *
+ * Only safe because callers pass the grid's posts, which exclude stories and
+ * highlights — a shortcode may legitimately appear in both the profile and a
+ * highlight, and those must stay distinct.
+ */
+export const dedupePostCopies = (posts: Post[]): Post[] => {
+  const winners = new Map<string, Post>();
+
+  for (const post of posts) {
+    const code = shortcode(post);
+    const existing = winners.get(code);
+    if (!existing || rankOf(post) < rankOf(existing)) winners.set(code, post);
+  }
+
+  // Preserve input order, keyed on the winner so ordering does not depend on
+  // which copy happened to be scanned first.
+  const emitted = new Set<string>();
+  const result: Post[] = [];
+  for (const post of posts) {
+    const code = shortcode(post);
+    if (emitted.has(code)) continue;
+    emitted.add(code);
+    result.push(winners.get(code)!);
+  }
+  return result;
+};
+
+/**
+ * The posts a tab displays.
+ *
+ * `posts` must already exclude stories and highlights (App passes `allPosts`).
+ */
+export const postsForTab = (posts: Post[], tab: Tab): Post[] => {
+  if (tab === 'saved') return [];
+
+  const unique = dedupePostCopies(posts);
+  if (tab === 'posts') return unique;
+  return unique.filter(makeIsReel(posts));
+};

src/lib/routing.test.ts

@@ -0,0 +1,114 @@
+import { describe, expect, it } from 'vitest';
+import { buildPath, findPostBySlug, parseRoute, postSlug, tabForSource } from './routing';
+import { Post } from '../types';
+
+const post = (id: string, source?: Post['source']): Post => ({
+  id, date: '2024-01-01', username: 'u', caption: '', media: [], thumbnail: '', source,
+});
+
+describe('parseRoute', () => {
+  it('reads the explorer root', () => {
+    expect(parseRoute('/')).toEqual({ archive: null, tab: 'posts', post: null });
+  });
+
+  it('reads a profile', () => {
+    expect(parseRoute('/4utumn07/')).toEqual({ archive: '4utumn07', tab: 'posts', post: null });
+  });
+
+  it('reads a profile without a trailing slash', () => {
+    expect(parseRoute('/4utumn07')).toEqual({ archive: '4utumn07', tab: 'posts', post: null });
+  });
+
+  it('reads a tab', () => {
+    expect(parseRoute('/4utumn07/reels/').tab).toBe('reels');
+    expect(parseRoute('/4utumn07/saved/').tab).toBe('saved');
+  });
+
+  it('reads a post in Instagram form', () => {
+    expect(parseRoute('/4utumn07/p/Db5tIoRCcvm/')).toEqual({
+      archive: '4utumn07', tab: 'posts', post: 'Db5tIoRCcvm',
+    });
+  });
+
+  it('decodes archive names containing spaces', () => {
+    expect(parseRoute('/Heejin_Bubble%20heejinmedia/').archive).toBe('Heejin_Bubble heejinmedia');
+  });
+
+  it('does not treat reserved prefixes as archives', () => {
+    for (const path of ['/api/archives', '/archives/x/y.jpg', '/assets/index.js']) {
+      expect(parseRoute(path).archive).toBeNull();
+    }
+  });
+
+  it('still understands the legacy query form', () => {
+    expect(parseRoute('/', '?a=4utumn07&t=reels&p=ABC')).toEqual({
+      archive: '4utumn07', tab: 'reels', post: 'ABC',
+    });
+  });
+
+  it('ignores an unknown tab', () => {
+    expect(parseRoute('/', '?a=u&t=bogus').tab).toBe('posts');
+  });
+});
+
+describe('buildPath', () => {
+  it.each([
+    [{ archive: null, tab: 'posts', post: null }, '/'],
+    [{ archive: '4utumn07', tab: 'posts', post: null }, '/4utumn07/'],
+    [{ archive: '4utumn07', tab: 'reels', post: null }, '/4utumn07/reels/'],
+    [{ archive: '4utumn07', tab: 'posts', post: 'Db5tIoRCcvm' }, '/4utumn07/p/Db5tIoRCcvm/'],
+  ] as const)('builds %j', (route, expected) => {
+    expect(buildPath(route as any)).toBe(expected);
+  });
+
+  it('omits the tab from a post URL, matching Instagram', () => {
+    expect(buildPath({ archive: 'u', tab: 'reels', post: 'ABC' })).toBe('/u/p/ABC/');
+  });
+
+  it('encodes archive names with spaces', () => {
+    expect(buildPath({ archive: 'a b', tab: 'posts', post: null })).toBe('/a%20b/');
+  });
+
+  it('round-trips through parseRoute', () => {
+    for (const route of [
+      { archive: '4utumn07', tab: 'posts' as const, post: null },
+      { archive: '4utumn07', tab: 'reels' as const, post: null },
+      { archive: 'Heejin_Bubble heejinmedia', tab: 'posts' as const, post: null },
+    ]) {
+      expect(parseRoute(buildPath(route))).toEqual(route);
+    }
+  });
+});
+
+describe('postSlug / findPostBySlug', () => {
+  it('uses the bare shortcode for base posts', () => {
+    expect(postSlug(post('Db5tIoRCcvm'))).toBe('Db5tIoRCcvm');
+  });
+
+  it('strips the sidecar directory from the slug', () => {
+    expect(postSlug(post('story highlights - u - Sunstory/C5dQPEYpd9W'))).toBe('C5dQPEYpd9W');
+  });
+
+  it('resolves a slug back to its post', () => {
+    const posts = [post('AAA'), post('4utumn07 - reels/BBB', 'reels')];
+    expect(findPostBySlug(posts, 'BBB')?.id).toBe('4utumn07 - reels/BBB');
+    expect(findPostBySlug(posts, 'AAA')?.id).toBe('AAA');
+  });
+
+  it('prefers an exact id match over a shortcode match', () => {
+    const posts = [post('x/ABC'), post('ABC')];
+    expect(findPostBySlug(posts, 'ABC')?.id).toBe('ABC');
+  });
+
+  it('returns undefined for an unknown slug', () => {
+    expect(findPostBySlug([post('AAA')], 'ZZZ')).toBeUndefined();
+  });
+});
+
+describe('tabForSource', () => {
+  it('sends reels to the reels tab and everything else to posts', () => {
+    expect(tabForSource('reels')).toBe('reels');
+    expect(tabForSource('posts')).toBe('posts');
+    expect(tabForSource(undefined)).toBe('posts');
+  });
+});

src/lib/routing.ts

@@ -0,0 +1,85 @@
+import { Post, SourceKind } from '../types';
+
+/**
+ * Instagram-shaped paths.
+ *
+ *   /                          the archive explorer
+ *   /<archive>/                a profile, posts tab
+ *   /<archive>/reels/          a profile, reels tab
+ *   /<archive>/saved/
+ *   /<archive>/p/<shortcode>/  a single post
+ *
+ * The older `?a=&t=&p=` query form is still parsed so existing links keep
+ * working; it is never written back.
+ */
+
+export type Tab = 'posts' | 'reels' | 'saved';
+
+const TABS: Tab[] = ['posts', 'reels', 'saved'];
+
+/**
+ * Path prefixes the app must never treat as an archive name, or a profile
+ * called "api" would shadow the backend.
+ */
+const RESERVED = new Set(['api', 'archives', 'assets', 'p', 'fonts', 'sw.js', 'manifest.webmanifest']);
+
+export interface Route {
+  archive: string | null;
+  tab: Tab;
+  /** Post shortcode, i.e. the trailing segment of a post id. */
+  post: string | null;
+}
+
+/**
+ * A post's URL slug.
+ *
+ * Sidecar posts carry a directory-scoped id (`story highlights - u - H/ABC`)
+ * so ids stay unique across sources, but only the shortcode belongs in a URL.
+ */
+export const postSlug = (post: Pick<Post, 'id'>): string => {
+  const tail = post.id.split('/').pop() ?? post.id;
+  return encodeURIComponent(tail);
+};
+
+/** Find the post a slug refers to, preferring an exact id match. */
+export const findPostBySlug = (posts: Post[], slug: string): Post | undefined => {
+  const decoded = decodeURIComponent(slug);
+  return posts.find(p => p.id === decoded)
+    ?? posts.find(p => (p.id.split('/').pop() ?? p.id) === decoded);
+};
+
+/** Which tab shows a given post, so a deep link lands on the right one. */
+export const tabForSource = (source?: SourceKind): Tab => (source === 'reels' ? 'reels' : 'posts');
+
+export const parseRoute = (pathname: string, search = ''): Route => {
+  const segments = pathname.split('/').filter(Boolean).map(decodeURIComponent);
+
+  if (segments.length && !RESERVED.has(segments[0])) {
+    const [archive, second, third] = segments;
+
+    if (second === 'p' && third) return { archive, tab: 'posts', post: third };
+    if (second && TABS.includes(second as Tab)) return { archive, tab: second as Tab, post: null };
+    return { archive, tab: 'posts', post: null };
+  }
+
+  // Legacy query form: ?a=<archive>&t=<tab>&p=<post id>
+  const params = new URLSearchParams(search);
+  const archive = params.get('a');
+  const tab = params.get('t');
+  return {
+    archive: archive || null,
+    tab: tab && TABS.includes(tab as Tab) ? (tab as Tab) : 'posts',
+    post: params.get('p'),
+  };
+};
+
+export const buildPath = ({ archive, tab, post }: Route): string => {
+  if (!archive) return '/';
+
+  const base = `/${encodeURIComponent(archive)}`;
+  // A post URL omits the tab, matching Instagram; the tab is re-derived from
+  // the post itself when the link is opened.
+  if (post) return `${base}/p/${post}/`;
+  if (tab !== 'posts') return `${base}/${tab}/`;
+  return `${base}/`;
+};

src/lib/thumbnail-worker.ts

@@ -0,0 +1,42 @@
+/**
+ * Thumbnail Generation Worker
+ * Uses OffscreenCanvas and createImageBitmap for high-performance,
+ * background-thread image resizing.
+ */
+
+self.onmessage = async (e: MessageEvent) => {
+  const { id, blob, width } = e.data;
+
+  try {
+    // 1. Create a bitmap from the blob (native browser decoding)
+    // We resize it DURING the decode step for maximum efficiency
+    const bitmap = await createImageBitmap(blob, {
+      resizeWidth: width,
+      resizeQuality: 'medium'
+    });
+
+    // 2. Use OffscreenCanvas to draw the resized bitmap
+    const canvas = new OffscreenCanvas(bitmap.width, bitmap.height);
+    const ctx = canvas.getContext('2d');
+    
+    if (!ctx) {
+      throw new Error('Could not get OffscreenCanvas context');
+    }
+
+    ctx.drawImage(bitmap, 0, 0);
+    
+    // 3. Convert to a small JPEG blob
+    const thumbnailBlob = await canvas.convertToBlob({
+      type: 'image/jpeg',
+      quality: 0.7
+    });
+
+    // 4. Release bitmap memory
+    bitmap.close();
+
+    // 5. Send result back
+    self.postMessage({ id, blob: thumbnailBlob });
+  } catch (err: any) {
+    self.postMessage({ id, error: err.message });
+  }
+};

src/lib/utils.ts

@@ -0,0 +1,26 @@
+import { clsx, type ClassValue } from 'clsx';
+import { twMerge } from 'tailwind-merge';
+import { format, parseISO } from 'date-fns';
+
+export function cn(...inputs: ClassValue[]) {
+  return twMerge(clsx(inputs));
+}
+
+/**
+ * Format an archive date, tolerating junk.
+ *
+ * Dates are derived from filenames and arbitrary archive JSON, and date-fns
+ * `format` throws a RangeError on an invalid date — which would take down the
+ * whole modal for one malformed name. Story highlights in particular carry no
+ * date at all when file mtimes are unavailable.
+ */
+export function formatDateSafe(date: string | undefined, pattern: string): string {
+  if (!date) return '';
+  try {
+    const parsed = parseISO(date);
+    if (Number.isNaN(parsed.getTime())) return '';
+    return format(parsed, pattern);
+  } catch {
+    return '';
+  }
+}

src/main.tsx

@@ -1,13 +1,34 @@
 import {StrictMode} from 'react';
 import {createRoot} from 'react-dom/client';
 import App from './App.tsx';
+import { ErrorBoundary } from './components/ErrorBoundary';
 import './index.css';
 import { registerSW } from 'virtual:pwa-register';
 
-registerSW();
+// Register service worker with automatic updates
+// and a periodic check every hour to ensure long-running sessions stay fresh.
+const updateSW = registerSW({
+  onRegistered(r) {
+    if (r) {
+      // Check for updates every hour
+      setInterval(() => {
+        r.update();
+      }, 60 * 60 * 1000);
+      console.log(`[PWA] v${__APP_VERSION__} registered; hourly update checks enabled.`);
+    }
+  },
+  onNeedRefresh() {
+    console.log('[PWA] New content available, reloading...');
+  },
+  onOfflineReady() {
+    console.log('[PWA] App is ready for offline use.');
+  }
+});
 
 createRoot(document.getElementById('root')!).render(
   <StrictMode>
-    <App />
+    <ErrorBoundary>
+      <App />
+    </ErrorBoundary>
   </StrictMode>,
 );

src/types/globals.d.ts

@@ -0,0 +1,9 @@
+/**
+ * Build-time constants.
+ *
+ * This file deliberately has no imports or exports: that keeps it an ambient
+ * script rather than a module, so the declarations below are global.
+ */
+
+/** Release version, injected by `define` in vite.config.ts. */
+declare const __APP_VERSION__: string;

src/types/index.ts

@@ -0,0 +1,123 @@
+export interface MediaFile {
+  name: string;
+  /**
+   * Path relative to the archive root (matching webkitRelativePath for local
+   * folders). Unlike `url`, this survives a page reload, so it is what the
+   * cache persists and what URLs are rehydrated from.
+   */
+  path: string;
+  url: string;
+  type: 'image' | 'video';
+  index: number;
+  size?: number;
+}
+
+/**
+ * Which sidecar directory a post came from. Archives store reels, stories and
+ * each story highlight in directories alongside the base profile; the viewer
+ * folds them into one profile and routes them by kind.
+ */
+export type SourceKind = 'posts' | 'reels' | 'stories' | 'highlight';
+
+export interface ArchiveSource {
+  kind: SourceKind;
+  /** Directory name relative to the archives root. */
+  dir: string;
+  /** Highlight title, for kind === 'highlight'. */
+  title?: string;
+}
+
+export interface Post {
+  id: string;
+  date: string;
+  username: string;
+  caption: string;
+  media: MediaFile[];
+  thumbnail: string;
+  isStory?: boolean;
+  /** Defaults to 'posts' for archives without sidecar directories. */
+  source?: SourceKind;
+  /** Highlight this post belongs to, for source === 'highlight'. */
+  highlightTitle?: string;
+}
+
+/**
+ * Common interface for both local File objects and remote server-side files.
+ */
+export interface ArchiveFile {
+  name: string;
+  webkitRelativePath: string;
+  size: number;
+  text(): Promise<string>;
+  arrayBuffer(): Promise<ArrayBuffer>;
+  url?: string;
+  /**
+   * A URL pointing at this file's contents. Local files mint a disk-backed
+   * blob: URL (no data is read into memory); remote files return their HTTP URL.
+   */
+  createObjectUrl(mimeHint?: string): string;
+  /** True when createObjectUrl() returns a blob: URL that must be revoked. */
+  readonly revocable: boolean;
+  /** Which sidecar directory this file came from, when known. */
+  source?: ArchiveSource;
+  /** Last-modified time (ms). Used to date items whose filename has no date. */
+  mtime?: number;
+}
+
+export interface ServerArchive {
+  name: string;
+  thumbnail: string;
+  path: string;
+  /** Null until the server has indexed this profile. */
+  fileCount: number | null;
+  /**
+   * Directory-mtime signature. Cheap for the server to compute and sufficient
+   * to detect changes, unlike a file count that would require a full walk.
+   */
+  signature?: string;
+  /** Base profile plus any sidecar directories folded into it. */
+  sources?: ArchiveSource[];
+}
+
+/** One entry from GET /api/archives/:name/files. */
+export interface ServerArchiveFile {
+  path: string;
+  size: number;
+  mtime: number;
+  kind: SourceKind;
+  title?: string;
+}
+
+export interface ProfileMetadata {
+  username: string;
+  fullName: string;
+  bio: string;
+  followerCount: number;
+  followingCount: number;
+  externalUrl: string;
+  profilePic: string | null;
+  allProfilePics: string[];
+}
+
+/** Shape of an archive entry persisted in IndexedDB. */
+export interface CacheData {
+  name: string;
+  isLocal: boolean;
+  fileCount: number;
+  /** Server archives: the signature this entry was built from. */
+  signature?: string;
+  posts: Post[];
+  stories: Post[];
+  /** Story-highlight items, grouped by `highlightTitle`. */
+  highlights?: Post[];
+  profileMetadata: ProfileMetadata;
+  timestamp: number;
+  /**
+   * Local archives only: whether a FileSystemDirectoryHandle was stored
+   * alongside this entry, meaning media URLs can be rehydrated without
+   * re-prompting for the folder.
+   */
+  hasDirectoryHandle?: boolean;
+  /** Path of the profile picture, for rehydration (local archives). */
+  profilePicPath?: string;
+}

src/types/react-augment.d.ts

@@ -0,0 +1,12 @@
+import 'react';
+
+declare module 'react' {
+  interface InputHTMLAttributes<T> {
+    /**
+     * Non-standard attribute that makes a file input select a whole directory.
+     * Supported in Chromium and WebKit; used as the fallback picker where the
+     * File System Access API is unavailable.
+     */
+    webkitdirectory?: string;
+  }
+}

vite.config.ts

@@ -1,17 +1,31 @@
 import tailwindcss from '@tailwindcss/vite';
 import react from '@vitejs/plugin-react';
 import path from 'path';
-import {defineConfig, loadEnv} from 'vite';
+import {defineConfig} from 'vite';
 import { VitePWA } from 'vite-plugin-pwa';
+import { createRequire } from 'module';
 
-export default defineConfig(({mode}) => {
+const { version } = createRequire(import.meta.url)('./package.json');
-  const env = loadEnv(mode, '.', '');
+
+export default defineConfig(() => {
   return {
+    /**
+     * The release version, compiled into the client.
+     *
+     * This is load-bearing, not cosmetic. The service worker precaches
+     * index.html *including its response headers*, so a server-side header
+     * change (a CSP fix, say) never reaches an installed PWA: nothing in the
+     * client build changed, the precache manifest is byte-identical, and the
+     * worker has no reason to update. Baking the version in means every release
+     * changes the bundle hash, which changes index.html, which invalidates the
+     * precache and re-fetches the shell with current headers.
+     */
+    define: { __APP_VERSION__: JSON.stringify(version) },
     plugins: [
       react(), 
       tailwindcss(),
       VitePWA({
-        registerType: 'prompt',
+        registerType: 'autoUpdate',
         manifest: {
           name: 'InstaArchive',
           short_name: 'InstaArchive',
@@ -21,42 +35,26 @@ export default defineConfig(({mode}) => {
           display: 'standalone',
           icons: [
             {
-              src: 'https://cdn-icons-png.flaticon.com/512/174/174855.png',
+              src: '/icon-512.png',
               sizes: '512x512',
               type: 'image/png',
               purpose: 'any maskable'
             },
             {
-              src: 'https://cdn-icons-png.flaticon.com/192/174/174855.png',
+              src: '/icon-192.png',
               sizes: '192x192',
               type: 'image/png'
             }
           ]
         },
         workbox: {
-          globPatterns: ['**/*.{js,css,html,ico,png,svg,woff,woff2}'],
+          navigateFallbackDenylist: [/^\/api/, /^\/archives/],
-          runtimeCaching: [
+          // Fonts and icons are bundled locally, so everything the shell needs
-            {
+          // is precached and no runtime third-party caching rule is required.
-              urlPattern: /^https:\/\/fonts\.googleapis\.com\/.*/i,
+          globPatterns: ['**/*.{js,css,html,ico,png,svg,woff,woff2}']
-              handler: 'CacheFirst',
-              options: {
-                cacheName: 'google-fonts-cache',
-                expiration: {
-                  maxEntries: 10,
-                  maxAgeSeconds: 60 * 60 * 24 * 365
-                },
-                cacheableResponse: {
-                  statuses: [0, 200]
-                }
-              }
-            }
-          ]
         }
       })
     ],
-    define: {
-      'process.env.GEMINI_API_KEY': JSON.stringify(env.GEMINI_API_KEY),
-    },
     resolve: {
       alias: {
         '@': path.resolve(__dirname, '.'),