feat(audio): add WAV and AIFF support + settings-style metadata menu

WAV/AIFF: library scan, quality probe, native tag read/write via embedded ID3 chunk (RIFF id3 / AIFF ID3), cover art, ReadFileMetadata, ExtractLyrics, and FLAC<->WAV/AIFF conversion (PCM, bit-depth preserved via ffprobe). Treat WAV/AIFF as lossless across all convert sheets (no bitrate picker, Lossless labels) via isLosslessConversionTarget. Native MIME maps for SAF. Redesign the track metadata three-dot menu to a settings-style grouped card with a single divider above Share.

lib/services/library_database.dart

@@ -2022,6 +2022,11 @@ class LibraryDatabase {
         return 'flac';
       case 'opus':
         return 'opus';
+      case 'wav':
+        return 'wav';
+      case 'aiff':
+      case 'aif':
+        return 'aiff';
       default:
         return 'mp3';
     }