fix: prefer local file for cover/lyrics save and update build dependencies

- Cover art: extract from downloaded file first, fall back to URL download
- Lyrics: check embedded lyrics/sidecar LRC before fetching online
- Add audioFilePath param to FetchAndSaveLyrics (Go, Kotlin, Swift, Dart)
- Handle SAF content:// URIs for lyrics extraction in Kotlin bridge
- Update Go 1.25.7 -> 1.25.8, Gradle 9.3.1 -> 9.4.1, Kotlin 2.2.21 -> 2.3.20
- Update NDK r27d -> r28b, Flutter FVM 3.41.4 -> 3.41.5
- Upgrade all Flutter and Go module dependencies to latest

lib/services/platform_bridge.dart

@@ -341,6 +341,7 @@ class PlatformBridge {
     required String spotifyId,
     required int durationMs,
     required String outputPath,
+    String audioFilePath = '',
   }) async {
     final result = await _channel.invokeMethod('fetchAndSaveLyrics', {
       'track_name': trackName,
@@ -348,6 +349,7 @@ class PlatformBridge {
       'spotify_id': spotifyId,
       'duration_ms': durationMs,
       'output_path': outputPath,
+      'audio_file_path': audioFilePath,
     });
     return jsonDecode(result as String) as Map<String, dynamic>;
   }