feat(tidal): convert M4A to MP3/Opus for HIGH quality, remove LOSSY option

- Add tidalHighFormat setting (mp3_320 or opus_128) for Tidal HIGH quality
- Add convertM4aToLossy() in FFmpegService for M4A to MP3/Opus conversion
- Remove inefficient LOSSY option (FLAC download then convert)
- Update download_queue_provider to handle HIGH quality conversion
- Clean up LOSSY references from download_service_picker and log messages
- Update Go backend: amazon.go, tidal.go, metadata.go improvements
- UI: minor updates to album, playlist, and home screens

android/app/proguard-rules.pro

@@ -28,6 +28,9 @@
 # FFmpeg Kit
 -keep class com.arthenica.ffmpegkit.** { *; }
 -keep class com.arthenica.smartexception.** { *; }
+# FFmpeg Kit (new fork package)
+-keep class com.antonkarpenko.ffmpegkit.** { *; }
+-keep class com.antonkarpenko.smartexception.** { *; }
 
 # Apache Tika (if used by FFmpeg)
 -dontwarn org.apache.tika.**