feat: Implement offline library management with IndexedDB support

- Added `useOfflineLibrary` hook for managing offline library state and synchronization.
- Created `OfflineLibraryManager` class for handling IndexedDB operations and syncing with Navidrome API.
- Implemented methods for retrieving and storing albums, artists, songs, and playlists.
- Added support for offline favorites management (star/unstar).
- Implemented playlist creation, updating, and deletion functionalities.
- Added search functionality for offline data.
- Created a manifest file for PWA support with icons and shortcuts.
- Added service worker file for caching and offline capabilities.

app/components/OfflineStatusIndicator.tsx

@@ -0,0 +1,65 @@
+'use client';
+
+import React from 'react';
+import { Badge } from '@/components/ui/badge';
+import { useOfflineLibrary } from '@/hooks/use-offline-library';
+import { Wifi, WifiOff, Download, Clock } from 'lucide-react';
+
+export function OfflineStatusIndicator() {
+  const { isOnline, stats, isSyncing, lastSync } = useOfflineLibrary();
+
+  if (!isOnline) {
+    return (
+      <Badge variant="secondary" className="flex items-center gap-1">
+        <WifiOff size={12} />
+        Offline Mode
+      </Badge>
+    );
+  }
+
+  if (isSyncing) {
+    return (
+      <Badge variant="default" className="flex items-center gap-1">
+        <Download size={12} className="animate-bounce" />
+        Syncing...
+      </Badge>
+    );
+  }
+
+  if (stats.pendingOperations > 0) {
+    return (
+      <Badge variant="outline" className="flex items-center gap-1">
+        <Clock size={12} />
+        {stats.pendingOperations} pending
+      </Badge>
+    );
+  }
+
+  return (
+    <Badge variant="default" className="flex items-center gap-1">
+      <Wifi size={12} />
+      Online
+    </Badge>
+  );
+}
+
+export function OfflineLibraryStats() {
+  const { stats, lastSync } = useOfflineLibrary();
+
+  if (!stats.albums && !stats.songs && !stats.artists) {
+    return null;
+  }
+
+  return (
+    <div className="text-xs text-muted-foreground space-y-1">
+      <div>
+        📀 {stats.albums} albums • 🎵 {stats.songs} songs • 👤 {stats.artists} artists
+      </div>
+      {lastSync && (
+        <div>
+          Last sync: {lastSync.toLocaleDateString()} at {lastSync.toLocaleTimeString()}
+        </div>
+      )}
+    </div>
+  );
+}