fix: improve voice and chat controls

apps/chanora_flutter/lib/widgets/voice_compact.dart

@@ -358,6 +358,7 @@ Future<void> showVoiceDetailsSheet(
   required String pttBoundInputClass,
   required bool isTouchOnly,
   required rust.BridgeAudioProcessingConfig initialAudioConfig,
+  bool onnxRuntimeAvailable = true,
   required ValueChanged<rust.BridgeTransmitMode> onModeChanged,
   required ValueChanged<int> onReleaseTailChanged,
   required ValueChanged<rust.BridgeAudioProcessingConfig> onAudioConfigChanged,
@@ -388,6 +389,7 @@ Future<void> showVoiceDetailsSheet(
           pttBoundInputClass: pttBoundInputClass,
           isTouchOnly: isTouchOnly,
           initialAudioConfig: initialAudioConfig,
+          onnxRuntimeAvailable: onnxRuntimeAvailable,
           onModeChanged: onModeChanged,
           onReleaseTailChanged: onReleaseTailChanged,
           onAudioConfigChanged: onAudioConfigChanged,
@@ -411,6 +413,7 @@ class _VoiceSheetBody extends StatefulWidget {
     required this.pttBoundInputClass,
     required this.isTouchOnly,
     required this.initialAudioConfig,
+    required this.onnxRuntimeAvailable,
     required this.onModeChanged,
     required this.onReleaseTailChanged,
     required this.onAudioConfigChanged,
@@ -428,6 +431,7 @@ class _VoiceSheetBody extends StatefulWidget {
   final String pttBoundInputClass;
   final bool isTouchOnly;
   final rust.BridgeAudioProcessingConfig initialAudioConfig;
+  final bool onnxRuntimeAvailable;
   final ValueChanged<rust.BridgeTransmitMode> onModeChanged;
   final ValueChanged<int> onReleaseTailChanged;
   final ValueChanged<rust.BridgeAudioProcessingConfig> onAudioConfigChanged;
@@ -462,6 +466,10 @@ class _VoiceSheetBodyState extends State<_VoiceSheetBody> {
     _audioProcessing = AudioProcessingConfigState.fromConfig(
       widget.initialAudioConfig,
     );
+    _audioProcessing.vadBackend = normalizedVadBackend(
+      _audioProcessing.vadBackend,
+      onnxRuntimeAvailable: widget.onnxRuntimeAvailable,
+    );
 
     // Poll audio stats at 250 ms so TX/RX counters and the level meter
     // update in real time while the sheet is open, independent of the parent.
@@ -777,19 +785,27 @@ class _VoiceSheetBodyState extends State<_VoiceSheetBody> {
             const SizedBox(height: 2),
             SegmentedButton<rust.BridgeVadBackend>(
               style: voiceSegmentedButtonStyle(theme),
-              segments: _isDesktopSileroVadHost
-                  ? desktopVadBackendSegments
-                  : vadBackendSegments,
+              segments: vadBackendSegmentsForAvailability(
+                desktop: _isDesktopSileroVadHost,
+                onnxRuntimeAvailable: widget.onnxRuntimeAvailable,
+              ),
               selected: {_audioProcessing.vadBackend},
               onSelectionChanged: (s) {
-                setState(() => _audioProcessing.vadBackend = s.first);
+                setState(
+                  () => _audioProcessing.vadBackend = normalizedVadBackend(
+                    s.first,
+                    onnxRuntimeAvailable: widget.onnxRuntimeAvailable,
+                  ),
+                );
                 _notifyAudioConfig();
               },
             ),
             if (_isDesktopSileroVadHost) ...[
               const SizedBox(height: 4),
               Text(
-                'Silero needs ONNX Runtime. WebRTC works without it.',
+                widget.onnxRuntimeAvailable
+                    ? 'Silero needs ONNX Runtime. WebRTC works without it.'
+                    : 'Silero is unavailable because ONNX Runtime was not found. WebRTC is selected.',
                 style: theme.textTheme.bodySmall?.copyWith(
                   color: theme.colorScheme.onSurfaceVariant,
                 ),