feat(flutter): persist voice settings and per-user volume (TODO-039,040)

Add SharedPreferences persistence for transmit mode, release tail,
input/output device. Per-user volume/mute persisted across sessions.

apps/chanora_flutter/lib/services/ui_preferences_service.dart

@@ -18,11 +18,19 @@ class UiSettings {
     this.host = '',
     this.nickname = '',
     this.themeMode = UiThemeMode.system,
+    this.transmitModeIndex,
+    this.releaseTailMs,
+    this.inputDeviceId,
+    this.outputDeviceId,
   });
 
   final String host;
   final String nickname;
   final UiThemeMode themeMode;
+  final int? transmitModeIndex;
+  final int? releaseTailMs;
+  final String? inputDeviceId;
+  final String? outputDeviceId;
 }
 
 class UiPreferencesService {
@@ -30,6 +38,10 @@ class UiPreferencesService {
   static const _nicknameKey = 'ui.nickname';
   static const _themeModeKey = 'ui.theme_mode';
   static const _permissionsExplainedKey = 'perms_explained';
+  static const _transmitModeIndexKey = 'voice.transmit_mode_index';
+  static const _releaseTailMsKey = 'voice.release_tail_ms';
+  static const _inputDeviceIdKey = 'audio.input_device_id';
+  static const _outputDeviceIdKey = 'audio.output_device_id';
 
   const UiPreferencesService();
 
@@ -39,6 +51,10 @@ class UiPreferencesService {
       host: prefs.getString(_hostKey) ?? '',
       nickname: prefs.getString(_nicknameKey) ?? '',
       themeMode: UiThemeMode.fromStorage(prefs.getString(_themeModeKey)),
+      transmitModeIndex: prefs.getInt(_transmitModeIndexKey),
+      releaseTailMs: prefs.getInt(_releaseTailMsKey),
+      inputDeviceId: prefs.getString(_inputDeviceIdKey),
+      outputDeviceId: prefs.getString(_outputDeviceIdKey),
     );
   }
 
@@ -53,6 +69,34 @@ class UiPreferencesService {
     await prefs.setString(_themeModeKey, themeMode.name);
   }
 
+  Future<void> saveTransmitModeIndex(int index) async {
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setInt(_transmitModeIndexKey, index);
+  }
+
+  Future<void> saveReleaseTailMs(int ms) async {
+    final prefs = await SharedPreferences.getInstance();
+    await prefs.setInt(_releaseTailMsKey, ms);
+  }
+
+  Future<void> saveInputDeviceId(String? id) async {
+    final prefs = await SharedPreferences.getInstance();
+    if (id == null) {
+      await prefs.remove(_inputDeviceIdKey);
+    } else {
+      await prefs.setString(_inputDeviceIdKey, id);
+    }
+  }
+
+  Future<void> saveOutputDeviceId(String? id) async {
+    final prefs = await SharedPreferences.getInstance();
+    if (id == null) {
+      await prefs.remove(_outputDeviceIdKey);
+    } else {
+      await prefs.setString(_outputDeviceIdKey, id);
+    }
+  }
+
   Future<bool> hasExplainedPermissions() async {
     final prefs = await SharedPreferences.getInstance();
     return prefs.getBool(_permissionsExplainedKey) ?? false;

apps/chanora_flutter/lib/widgets/audio_device_list_tile.dart

@@ -27,6 +27,7 @@ class AudioDeviceListTile extends StatefulWidget {
     AudioDeviceListLoader? loadDevices,
     AudioDeviceSetter? setInputDevice,
     AudioDeviceSetter? setOutputDevice,
+    this.onDeviceChanged,
   }) : loadDevices = loadDevices ?? rust.listAudioDevices,
        setInputDevice = setInputDevice ?? rust.setInputDevice,
        setOutputDevice = setOutputDevice ?? rust.setOutputDevice;
@@ -46,6 +47,10 @@ class AudioDeviceListTile extends StatefulWidget {
   /// Selects an output device.
   final AudioDeviceSetter setOutputDevice;
 
+  /// Called after a device selection succeeds. Receives the device id
+  /// (null for system default).
+  final ValueChanged<String?>? onDeviceChanged;
+
   @override
   State<AudioDeviceListTile> createState() => _AudioDeviceListTileState();
 }
@@ -88,6 +93,7 @@ class _AudioDeviceListTileState extends State<AudioDeviceListTile> {
     setState(() {
       _selectedDeviceId = deviceId;
     });
+    widget.onDeviceChanged?.call(deviceId);
 
     final selectedName = _selectedDevice?.name ?? 'System default';
     ScaffoldMessenger.of(context).showSnackBar(

apps/chanora_flutter/lib/widgets/snapshot_view.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:shared_preferences/shared_preferences.dart';
 
 import '../l10n/generated/app_localizations.dart';
 import '../services/channel_spacer.dart';
@@ -571,11 +572,40 @@ class _ClientVolumePreference {
 }
 
 class _ClientVolumePreferences extends ChangeNotifier {
-  _ClientVolumePreferences._();
+  _ClientVolumePreferences._() {
+    _load();
+  }
 
   static final instance = _ClientVolumePreferences._();
 
+  static const _prefsKey = 'client_volume_prefs';
+
   final Map<BigInt, _ClientVolumePreference> _byClientId = {};
+  bool _loaded = false;
+
+  Future<void> _load() async {
+    if (_loaded) return;
+    _loaded = true;
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final raw = prefs.getStringList(_prefsKey) ?? const [];
+      for (final entry in raw) {
+        final parts = entry.split(':');
+        if (parts.length == 3) {
+          final id = BigInt.tryParse(parts[0]);
+          final volume = double.tryParse(parts[1]);
+          final muted = parts[2] == '1';
+          if (id != null && volume != null) {
+            _byClientId[id] = _ClientVolumePreference(
+              volume: volume,
+              muted: muted,
+            );
+          }
+        }
+      }
+      notifyListeners();
+    } catch (_) {}
+  }
 
   _ClientVolumePreference preferenceFor(BigInt clientId) {
     return _byClientId[clientId] ?? const _ClientVolumePreference();
@@ -588,6 +618,17 @@ class _ClientVolumePreferences extends ChangeNotifier {
       _byClientId.remove(clientId);
     }
     notifyListeners();
+    _save();
+  }
+
+  Future<void> _save() async {
+    try {
+      final prefs = await SharedPreferences.getInstance();
+      final raw = _byClientId.entries
+          .map((e) => '${e.key}:${e.value.volume}:${e.value.muted ? 1 : 0}')
+          .toList();
+      await prefs.setStringList(_prefsKey, raw);
+    } catch (_) {}
   }
 }
 

apps/chanora_flutter/lib/widgets/voice_settings.dart

@@ -47,6 +47,8 @@ class VoiceSettingsDialog extends StatefulWidget {
     this.talkPower,
     this.neededTalkPower,
     this.talkPowerGranted,
+    this.onInputDeviceChanged,
+    this.onOutputDeviceChanged,
   });
 
   final rust.BridgeTransmitMode initialMode;
@@ -58,6 +60,8 @@ class VoiceSettingsDialog extends StatefulWidget {
   final int? talkPower;
   final int? neededTalkPower;
   final bool? talkPowerGranted;
+  final ValueChanged<String?>? onInputDeviceChanged;
+  final ValueChanged<String?>? onOutputDeviceChanged;
 
   @override
   State<VoiceSettingsDialog> createState() => _VoiceSettingsDialogState();
@@ -207,13 +211,15 @@ class _VoiceSettingsDialogState extends State<VoiceSettingsDialog> {
               if (!isAndroidHost && !isIosHost) ...[
                 const Divider(height: 24),
                 const VoiceSectionHeader('Audio devices'),
-                const AudioDeviceListTile(
+                AudioDeviceListTile(
                   label: 'Input',
                   kind: AudioDeviceKind.input,
+                  onDeviceChanged: widget.onInputDeviceChanged,
                 ),
-                const AudioDeviceListTile(
+                AudioDeviceListTile(
                   label: 'Output',
                   kind: AudioDeviceKind.output,
+                  onDeviceChanged: widget.onOutputDeviceChanged,
                 ),
                 const SizedBox(height: 8),
               ],

apps/chanora_flutter/test/services/ui_preferences_service_test.dart

@@ -67,4 +67,44 @@ void main() {
 
     expect(settings.themeMode, UiThemeMode.system);
   });
+
+  test('loads null voice settings when unset', () async {
+    final settings = await service.loadSettings();
+
+    expect(settings.transmitModeIndex, isNull);
+    expect(settings.releaseTailMs, isNull);
+    expect(settings.inputDeviceId, isNull);
+    expect(settings.outputDeviceId, isNull);
+  });
+
+  test('saves and loads transmit mode index', () async {
+    await service.saveTransmitModeIndex(1);
+    final settings = await service.loadSettings();
+
+    expect(settings.transmitModeIndex, 1);
+  });
+
+  test('saves and loads release tail ms', () async {
+    await service.saveReleaseTailMs(300);
+    final settings = await service.loadSettings();
+
+    expect(settings.releaseTailMs, 300);
+  });
+
+  test('saves and loads audio device ids', () async {
+    await service.saveInputDeviceId('input-123');
+    await service.saveOutputDeviceId('output-456');
+    final settings = await service.loadSettings();
+
+    expect(settings.inputDeviceId, 'input-123');
+    expect(settings.outputDeviceId, 'output-456');
+  });
+
+  test('removes audio device id when set to null', () async {
+    await service.saveInputDeviceId('input-123');
+    await service.saveInputDeviceId(null);
+    final settings = await service.loadSettings();
+
+    expect(settings.inputDeviceId, isNull);
+  });
 }