fix: read xz sidecars by buffer, page carousel with arrows, stop backdrop flash

Instaloader metadata was silently lost
Every .json.xz failed with "Failed to fetch" during a scan, though the same URL
fetched fine on its own. RemoteArchiveFile.stream() started a fetch, piped the
body into a TransformStream and returned the readable immediately — nothing
caught a fetch rejection, and the decompressor stops reading at the end of the
xz member, so the response body was never drained or cancelled. Across ~190
sidecars that exhausted the connection pool.

Everything Instaloader archives carry lives in those files, so the failure was
invisible but total. rivvsofficial reported 188 posts, no stories, 0 followers
and a placeholder bio; it now reports 68 posts, 120 stories, 10,337 followers
and the real name, bio and link — 68 + 120 = 188, matching the sidecars exactly
(106 GraphStoryVideo + 14 GraphStoryImage = 120).

These sidecars are a few KB, so they are now read into memory before
decompressing. stream() was left unused by that change and is removed from the
interface and both implementations rather than kept as a trap.

Arrow keys page the carousel
They moved between posts, which contradicted the arrows drawn on the carousel
itself. Arrows now page slides; , and . move between posts, alongside the side
buttons.

Backdrop cross-fade
AnimatePresence had no exit variant, so the outgoing scan backdrop was removed
instantly while its replacement faded in over 1.5s, exposing the pale page
behind it as a white flash. Layers now stack: the outgoing image holds full
opacity until covered, and the 0.4 moved onto the group so overlapping layers
don't darken as they cross. Measured over a real scan: 152 cross-fades with a
layer always opaque, except the opening fade-in where nothing is underneath.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011uBWhwV3wFQ5MBCcMHHem7

.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 +1,109 @@
+# 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.
+
+### 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`.
+- Sets CSP and related security headers. The CSP allows `blob:`/`data:` for media and `unsafe-inline` styles (the animation library sets inline styles); scripts stay same-origin only.
+- `os.userInfo()` throws for a UID with no `/etc/passwd` entry, which is what `--user 1234:1234` produces — use `describeUser()`.
+
+### Deployment
+
+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

@@ -7,7 +7,7 @@ WORKDIR /app
 COPY package*.json ./
 RUN npm ci
 
-# Copy source and build frontend
+# Copy source and build (frontend and server)
 COPY . .
 RUN npm run build
 
@@ -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
 
@@ -25,14 +28,18 @@ 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/server.ts ./
+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
 
-# Start server using tsx
+# Start server
-CMD ["npx", "tsx", "server.ts"]
+CMD ["node", "server.js"]

GEMINI.md

@@ -2,38 +2,68 @@
 
 ## Project Overview
 
-**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 allows users to load local archive directories (either official Instagram exports or Instaloader format) and browse posts, reels, and stories.
+**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
-- **Local Archive Loading:** Uses the `webkitdirectory` API to scan and process local files securely on the client-side.
+- **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.
-- **Support for Multiple Formats:** Recognizes official Instagram export structures and Instaloader regex-based naming conventions.
+- **Persistent Caching:** Uses `idb-keyval` (IndexedDB) to cache parsed metadata. Subsequent loads are near-instant.
-- **Compressed Metadata**: Support for `.json.xz` file decompression using `xz-decompress` (WASM-powered).
+  - **Metadata:** Caches profile info and post lists for both remote AND local archives.
-- **Dynamic Media Grid**: Customizable grid layouts (1:1 and 3:4 aspect ratios) with adjustable offsets ("bumps") for aesthetic alignment.
+  - **Thumbnails:** High-res images (>1MiB) and videos have thumbnails generated and cached in IndexedDB with the `thumb_` prefix.
-- **Story Viewer**: Native-like story experience with segmented progress bars, automated playback, audio controls, and chronological sorting.
+- **Background Media Processing:**
-- **Auto-Unmute**: Videos default to unmuted when opened in full view for a better user experience.
+  - **High-Res Images:** A dedicated Web Worker (`thumbnail-worker.ts`) handles image resizing using `OffscreenCanvas` and `createImageBitmap` to prevent main-thread jank.
-- **PWA Ready**: Built with `vite-plugin-pwa` for offline capabilities and a standalone application experience.
+  - **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`)
-- **Utility:** Date-fns, clsx, tailwind-merge
+- **Persistence:** IndexedDB (`idb-keyval`)
-- **Decompression**: xz-decompress (WASM)
+- **Backend:** Express, tsx
+- **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 preview`: Locally preview the production build.
+- `npm run server`: Start production-ready backend.
-- `npm run lint`: Execute TypeScript type-checking (`tsc --noEmit`).
+- `npm run lint`: Execute TypeScript type-checking.
 
-## Development Conventions
+## Production Deployment
-- **Component Architecture:** Functional components with modern hooks.
+The project is containerized. It expects a volume mount at `/archives` containing subdirectories for each user.
-- **State Management**: React `useState`, `useMemo`, and `useCallback` for optimized performance during large archive scans.
-- **File Handling:** Privacy-focused client-side scanning of archive directories.
-- **Project Structure:**
-  - `src/App.tsx`: Main entry point containing application logic and UI components.
-  - `src/main.tsx`: React DOM mounting.
-  - `src/index.css`: Global styles and Tailwind imports.
-  - `vite.config.ts`: Project build and PWA configuration.

README.md

@@ -4,40 +4,100 @@ A high-performance React PWA for browsing archived Instagram data with a native-
 
 ## Features
 
-- **Local Privacy**: All processing is done client-side using browser APIs. Your data never leaves your computer.
+- **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.
-- **Multiple Formats**: Supports official Instagram JSON exports and Instaloader regex-based naming conventions.
+- **High-Res Performance**: Handles 50MP+ images effortlessly using a background Web Worker and a memory-safe serial processing queue.
-- **Metadata Support**: Robust parsing of `.json` and `.json.xz` files for captions, timestamps, and story metadata.
+- **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.
+- **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.
+- **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.
-- **Media Grid**: Customizable 1:1 or 3:4 grid views with adjustable offsets for aesthetic alignment.
+- **Navigation Protection**: Intercepts accidental browser "Back" or "Refresh" actions to protect your current session.
-- **Auto-Deduplication**: Intelligently prefers video files over thumbnail images for the same post.
 
-## Run Locally
+## Deployment
+
+### Docker (Recommended)
+
+The easiest way to run InstaArchive is using Docker.
+
+```bash
+docker run -d \
+  -p 3000:3000 \
+  -v /path/to/your/archives:/archives:ro \
+  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:
+
+```yaml
+services:
+  instaarchive:
+    image: ghcr.io/ergosteur/instaarchive-viewer:latest
+    ports:
+      - "3000:3000"
+    volumes:
+      - ./archives:/archives:ro,z # ,z handles SELinux permissions
+```
+
+### Troubleshooting Permissions
+
+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
+
+Place your archive folders inside the mounted `/archives` directory. The directory name will be used as the account username.
+
+### Example Structure:
+```text
+archives/
+├── wanderlust_explorer/          # Instaloader format
+│   ├── 2024-01-01_12-00-00_UTC.jpg
+│   ├── 2024-01-01_12-00-00_UTC.json.xz
+│   └── wanderlust_explorer_profile_pic.jpg
+└── pixel_architect/             # Instagram Export format
+    ├── 2023-12-25_pixel_architect - post_123.jpg
+    ├── 2023-12-25_pixel_architect - post_123.json
+    └── pixel_architect.jpg
+```
+
+## Local Development
 
 **Prerequisites:** Node.js (LTS recommended)
 
-1. **Install dependencies:**
+1. **Install dependencies:** `npm install`
-   ```bash
+2. **Start dev server:** `npm run dev` (Frontend on port 3000)
-   npm install
+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)
-
-2. **Start the development server:**
-   ```bash
-   npm run dev
-   ```
-
-3. **Open in browser:**
-   Navigate to `http://localhost:3000` and select your Instagram archive directory.
-
-## Building for Production
-
-To generate a production-ready build in the `dist` folder:
-
-```bash
-npm run build
-```
-
-To preview the build:
-
-```bash
-npm run preview
-```

compose.yml

@@ -0,0 +1,17 @@
+services:
+  instaarchive:
+    image: ghcr.io/ergosteur/instaarchive-viewer:latest
+    ports:
+      - "3000:3000"
+    volumes:
+      - ./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

@@ -1,21 +1,23 @@
 {
-  "name": "react-example",
+  "name": "instaarchive-viewer",
   "private": true,
-  "version": "1.1.0",
+  "version": "1.6.0",
   "type": "module",
   "scripts": {
     "dev": "vite --port=3000 --host=0.0.0.0",
-    "build": "vite build",
+    "build": "vite build && npm run build:server",
+    "build:server": "tsc server.ts --esModuleInterop --module ESNext --target ES2022 --moduleResolution bundler --outDir dist-server",
     "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",
@@ -33,10 +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();
 
@@ -11,77 +13,152 @@ const __dirname = path.dirname(__filename);
 
 const app = express();
 const PORT = process.env.PORT || 3001;
-const ARCHIVES_DIR = process.env.ARCHIVES_DIR || path.join(__dirname, '_sample-archives');
+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(`Warning: Archives directory not found at ${ARCHIVES_DIR}. Creating it...`);
+  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:",
+    "script-src 'self'",
+    "style-src 'self' 'unsafe-inline'",
+    "font-src 'self'",
+    "connect-src 'self'",
+    "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: ${archiveName}`);
+    return null;
+  }
+  return resolved;
+};
+
+// API: List archives, grouped by profile. Costs one stat per source directory.
 app.get('/api/archives', (req, res) => {
   try {
-    const items = fs.readdirSync(ARCHIVES_DIR, { withFileTypes: true });
+    const groups = index.groups();
-    const archives = items
+    const archives = Array.from(groups.entries()).map(([owner, sources]) => ({
-      .filter(item => item.isDirectory())
+      name: owner,
-      .map(item => {
+      thumbnail: index.thumbnailFor(owner, sources),
-        // Try to find a profile pic or first image for the thumbnail
+      path: owner,
-        const archivePath = path.join(ARCHIVES_DIR, item.name);
+      // Null until that profile has been indexed; the client treats it as unknown.
-        const files = fs.readdirSync(archivePath);
+      fileCount: index.countFor(sources),
-        
+      // Directory mtimes: cheap to compute and enough to invalidate a stale cache.
-        let thumbnail = '';
+      signature: index.signatureFor(sources),
-        const profilePic = files.find(f => f.toLowerCase().includes('_profile_pic.jpg') || f.toLowerCase() === `${item.name.toLowerCase()}.jpg`);
+      sources,
-        if (profilePic) {
+    }));
-          thumbnail = `/archives/${item.name}/${profilePic}`;
+    console.log(`[API] Returning ${archives.length} archives.`);
-        } else {
-          const firstImage = files.find(f => /\.(jpg|jpeg|png|webp)$/i.test(f));
-          if (firstImage) thumbnail = `/archives/${item.name}/${firstImage}`;
-        }
-
-        return {
-          name: item.name,
-          thumbnail,
-          path: item.name,
-          fileCount: files.length
-        };
-      });
     res.json(archives);
-  } catch (err) {
+  } catch (err: any) {
-    console.error('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);
@@ -89,8 +166,14 @@ 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/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] Service Worker registered and update interval set.');
+    }
+  },
+  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/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 +1,16 @@
 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';
 
-export default defineConfig(({mode}) => {
+export default defineConfig(() => {
-  const env = loadEnv(mode, '.', '');
   return {
     plugins: [
       react(), 
       tailwindcss(),
       VitePWA({
-        registerType: 'prompt',
+        registerType: 'autoUpdate',
         manifest: {
           name: 'InstaArchive',
           short_name: 'InstaArchive',
@@ -21,42 +20,26 @@ 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, '.'),