feat: modularize scanner, enhance carousel preloading, and improve PWA updates

Summary of changes:
- Extracted archive scanning logic into a modular 'useArchiveScanner' hook for better maintainability and performance.
- Refined PostModal carousel with intelligent media preloading and smoother, jitter-free transitions.
- Optimized image rendering with 'decoding=async' and removed 'black flashes' between slide changes.
- Updated PWA configuration to 'autoUpdate' with hourly periodic checks for fresh content.
- Fixed several bugs including stories sorting, permalink parameter cleanup, and profile metadata cache restoration.
- Comprehensive updates to documentation (README.md and GEMINI.md) reflecting the new architecture.

src/main.tsx

@@ -4,7 +4,25 @@ import App from './App.tsx';
 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>