feat: add AAC lossy target and toggle for Apple Music eLRC word sync

The HIGH-quality lossy format picker can now produce an AAC/M4A 320 kbps output alongside MP3 and Opus. FFmpegService.convertM4aToLossy/convertAudioFormat, the Dart queue pipeline, the Kotlin finalizer, and the library database format helper all route .m4a through a unified aac codec path and tag the resulting file with the M4A metadata writer. The Lossy Format setting gains a new option, and the track metadata convert dialog lists AAC next to the other targets.

Apple Music lyrics gain a 'eLRC word sync' switch (default off). When disabled the pax-to-LRC formatter strips inline word timestamps, producing line-synced LRC that is safer for players that choke on eLRC; enabling it restores the previous word-by-word behaviour. The change propagates through SetLyricsFetchOptions and invalidates the global lyrics cache on toggle.

Broad l10n migration: roughly 400 previously hardcoded English strings across queue, settings, track metadata, repo, audio analysis, setup and extension screens now live in the ARB catalog, with matching plural/placeholder forms. No behaviour change beyond localisation. Existing and new unit tests (lyrics eLRC toggle and Dart settings round-trip) pass.

lib/widgets/audio_analysis_widget.dart

@@ -182,7 +182,9 @@ class _AudioAnalysisCardState extends State<AudioAnalysisCard> {
         await _clearCache(widget.filePath);
       }
 
-      final cached = forceRefresh ? null : await _loadFromCache(widget.filePath);
+      final cached = forceRefresh
+          ? null
+          : await _loadFromCache(widget.filePath);
       AudioAnalysisData data;
       bool fromCache = false;
 
@@ -571,10 +573,7 @@ class _AudioAnalysisCardState extends State<AudioAnalysisCard> {
                 tooltip: l10n.audioAnalysisRescan,
                 visualDensity: VisualDensity.compact,
                 padding: EdgeInsets.zero,
-                constraints: const BoxConstraints(
-                  minWidth: 32,
-                  minHeight: 32,
-                ),
+                constraints: const BoxConstraints(minWidth: 32, minHeight: 32),
                 color: cs.onErrorContainer,
                 onPressed: () => _analyze(forceRefresh: true),
               ),
@@ -904,9 +903,9 @@ class _AudioInfoCard extends StatelessWidget {
                   icon: Icons.surround_sound,
                   label: context.l10n.audioAnalysisChannels,
                   value: data.channels == 2
-                      ? 'Stereo'
+                      ? context.l10n.audioAnalysisStereo
                       : data.channels == 1
-                      ? 'Mono'
+                      ? context.l10n.audioAnalysisMono
                       : '${data.channels}',
                   cs: cs,
                 ),

lib/widgets/download_service_picker.dart

@@ -380,7 +380,7 @@ class _ServiceHealthDot extends StatelessWidget {
   Widget build(BuildContext context) {
     final color = _serviceHealthColor(status);
     return Tooltip(
-      message: _serviceHealthTooltip(status),
+      message: _serviceHealthTooltip(context, status),
       child: Container(
         width: 8,
         height: 8,
@@ -404,16 +404,16 @@ Color _serviceHealthColor(String status) {
   }
 }
 
-String _serviceHealthTooltip(String status) {
+String _serviceHealthTooltip(BuildContext context, String status) {
   switch (status) {
     case 'online':
-      return 'Service online';
+      return context.l10n.extensionHealthServiceOnline;
     case 'degraded':
-      return 'Service degraded';
+      return context.l10n.extensionHealthServiceDegraded;
     case 'offline':
-      return 'Service offline';
+      return context.l10n.extensionHealthServiceOffline;
     default:
-      return 'Service status unknown';
+      return context.l10n.extensionHealthServiceUnknown;
   }
 }
 

lib/widgets/priority_settings_scaffold.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:spotiflac_android/l10n/l10n.dart';
 import 'package:spotiflac_android/utils/app_bar_layout.dart';
 
 class PrioritySettingsScaffold extends StatelessWidget {
@@ -6,7 +7,7 @@ class PrioritySettingsScaffold extends StatelessWidget {
   final String title;
   final String description;
   final String infoText;
-  final String saveLabel;
+  final String? saveLabel;
   final EdgeInsetsGeometry descriptionPadding;
   final List<Widget> slivers;
   final Future<void> Function() onSave;
@@ -21,7 +22,7 @@ class PrioritySettingsScaffold extends StatelessWidget {
     required this.slivers,
     required this.onSave,
     required this.onConfirmDiscard,
-    this.saveLabel = 'Save',
+    this.saveLabel,
     this.descriptionPadding = const EdgeInsets.fromLTRB(16, 4, 16, 8),
   });
 
@@ -67,7 +68,10 @@ class PrioritySettingsScaffold extends StatelessWidget {
               ),
               actions: [
                 if (hasChanges)
-                  TextButton(onPressed: onSave, child: Text(saveLabel)),
+                  TextButton(
+                    onPressed: onSave,
+                    child: Text(saveLabel ?? context.l10n.dialogSave),
+                  ),
               ],
               flexibleSpace: LayoutBuilder(
                 builder: (context, constraints) {