feat: add local library albums to Albums tab with unified grid and LocalAlbumScreen

- Add local library albums as clickable cards in Albums filter
- Merge downloaded and local albums into single unified grid (fix layout gaps)
- Create LocalAlbumScreen for viewing local album details with:
  - Cover art display with dominant color extraction
  - Album info card with Local badge and quality info
  - Track list with disc grouping support
  - Selection mode with delete functionality
  - UI consistent with DownloadedAlbumScreen (Card + ListTile layout)
- Add singles filter support for local library singles
- Add extractDominantColorFromFile to PaletteService
- Add delete(id) method to LibraryDatabase
- Add removeItem(id) method to LocalLibraryNotifier
- Update CHANGELOG.md for v3.4.0

lib/services/library_database.dart

@@ -14,6 +14,7 @@ class LocalLibraryItem {
   final String albumName;
   final String? albumArtist;
   final String filePath;
+  final String? coverPath; // Path to extracted cover art
   final DateTime scannedAt;
   final String? isrc;
   final int? trackNumber;
@@ -32,6 +33,7 @@ class LocalLibraryItem {
     required this.albumName,
     this.albumArtist,
     required this.filePath,
+    this.coverPath,
     required this.scannedAt,
     this.isrc,
     this.trackNumber,
@@ -51,6 +53,7 @@ class LocalLibraryItem {
     'albumName': albumName,
     'albumArtist': albumArtist,
     'filePath': filePath,
+    'coverPath': coverPath,
     'scannedAt': scannedAt.toIso8601String(),
     'isrc': isrc,
     'trackNumber': trackNumber,
@@ -71,6 +74,7 @@ class LocalLibraryItem {
         albumName: json['albumName'] as String,
         albumArtist: json['albumArtist'] as String?,
         filePath: json['filePath'] as String,
+        coverPath: json['coverPath'] as String?,
         scannedAt: DateTime.parse(json['scannedAt'] as String),
         isrc: json['isrc'] as String?,
         trackNumber: json['trackNumber'] as int?,
@@ -109,7 +113,7 @@ class LibraryDatabase {
     
     return await openDatabase(
       path,
-      version: 1,
+      version: 2, // Bumped version for cover_path migration
       onCreate: _createDB,
       onUpgrade: _upgradeDB,
     );
@@ -126,6 +130,7 @@ class LibraryDatabase {
         album_name TEXT NOT NULL,
         album_artist TEXT,
         file_path TEXT NOT NULL UNIQUE,
+        cover_path TEXT,
         scanned_at TEXT NOT NULL,
         isrc TEXT,
         track_number INTEGER,
@@ -150,7 +155,12 @@ class LibraryDatabase {
   
   Future<void> _upgradeDB(Database db, int oldVersion, int newVersion) async {
     _log.i('Upgrading library database from v$oldVersion to v$newVersion');
-    // Future migrations go here
+    
+    if (oldVersion < 2) {
+      // Add cover_path column
+      await db.execute('ALTER TABLE library ADD COLUMN cover_path TEXT');
+      _log.i('Added cover_path column');
+    }
   }
   
   /// Convert JSON format (camelCase) to DB row (snake_case)
@@ -162,6 +172,7 @@ class LibraryDatabase {
       'album_name': json['albumName'],
       'album_artist': json['albumArtist'],
       'file_path': json['filePath'],
+      'cover_path': json['coverPath'],
       'scanned_at': json['scannedAt'],
       'isrc': json['isrc'],
       'track_number': json['trackNumber'],
@@ -184,6 +195,7 @@ class LibraryDatabase {
       'albumName': row['album_name'],
       'albumArtist': row['album_artist'],
       'filePath': row['file_path'],
+      'coverPath': row['cover_path'],
       'scannedAt': row['scanned_at'],
       'isrc': row['isrc'],
       'trackNumber': row['track_number'],
@@ -333,6 +345,12 @@ class LibraryDatabase {
     await db.delete('library', where: 'file_path = ?', whereArgs: [filePath]);
   }
   
+  /// Delete by ID
+  Future<void> delete(String id) async {
+    final db = await database;
+    await db.delete('library', where: 'id = ?', whereArgs: [id]);
+  }
+  
   /// Delete items where file no longer exists
   Future<int> cleanupMissingFiles() async {
     final db = await database;

lib/services/notification_service.dart

@@ -145,12 +145,20 @@ class NotificationService {
     required String artistName,
     int? completedCount,
     int? totalCount,
+    bool alreadyInLibrary = false,
   }) async {
     if (!_isInitialized) await initialize();
 
-    final title = completedCount != null && totalCount != null
-        ? 'Download Complete ($completedCount/$totalCount)'
-        : 'Download Complete';
+    String title;
+    if (alreadyInLibrary) {
+      title = completedCount != null && totalCount != null
+          ? 'Already in Library ($completedCount/$totalCount)'
+          : 'Already in Library';
+    } else {
+      title = completedCount != null && totalCount != null
+          ? 'Download Complete ($completedCount/$totalCount)'
+          : 'Download Complete';
+    }
 
     const androidDetails = AndroidNotificationDetails(
       channelId,

lib/services/palette_service.dart

@@ -1,3 +1,4 @@
+import 'dart:io';
 import 'package:flutter/material.dart';
 import 'package:cached_network_image/cached_network_image.dart';
 import 'package:palette_generator/palette_generator.dart';
@@ -46,6 +47,40 @@ class PaletteService {
     }
   }
 
+  /// Extract dominant color from a local file path
+  Future<Color?> extractDominantColorFromFile(String? filePath) async {
+    if (filePath == null || filePath.isEmpty) return null;
+
+    final cached = _colorCache[filePath];
+    if (cached != null) {
+      return cached;
+    }
+
+    try {
+      final file = File(filePath);
+      if (!await file.exists()) return null;
+      
+      final paletteGenerator = await PaletteGenerator.fromImageProvider(
+        FileImage(file),
+        size: const Size(64, 64),
+        maximumColorCount: 8,
+      );
+      
+      final color = paletteGenerator.dominantColor?.color ??
+          paletteGenerator.vibrantColor?.color ??
+          paletteGenerator.mutedColor?.color;
+      
+      if (color != null) {
+        _colorCache[filePath] = color;
+      }
+      
+      return color;
+    } catch (e) {
+      debugPrint('PaletteService file error: $e');
+      return null;
+    }
+  }
+
   /// Clear the color cache
   void clearCache() {
     _colorCache.clear();

lib/services/platform_bridge.dart

@@ -823,6 +823,14 @@ static Future<Map<String, dynamic>> downloadWithExtensions({
 
   // ==================== LOCAL LIBRARY SCANNING ====================
 
+  /// Set the directory for caching extracted cover art
+  static Future<void> setLibraryCoverCacheDir(String cacheDir) async {
+    _log.i('setLibraryCoverCacheDir: $cacheDir');
+    await _channel.invokeMethod('setLibraryCoverCacheDir', {
+      'cache_dir': cacheDir,
+    });
+  }
+
   /// Scan a folder for audio files and read their metadata
   /// Returns a list of track metadata
   static Future<List<Map<String, dynamic>>> scanLibraryFolder(String folderPath) async {