chore: restore product scaffold to rollback baseline

apps/chanora_flutter/lib/widgets/voice_settings.dart

@@ -67,7 +67,6 @@ class VoiceSettingsDialog extends StatefulWidget {
     this.pttLevel = '',
     this.pttBackendId = '',
     this.pttBoundInputClass = '',
-    this.onnxRuntimeAvailable = true,
     this.talkPower,
     this.neededTalkPower,
     this.talkPowerGranted,
@@ -79,7 +78,6 @@ class VoiceSettingsDialog extends StatefulWidget {
   final String pttLevel;
   final String pttBackendId;
   final String pttBoundInputClass;
-  final bool onnxRuntimeAvailable;
   final int? talkPower;
   final int? neededTalkPower;
   final bool? talkPowerGranted;
@@ -103,10 +101,6 @@ class _VoiceSettingsDialogState extends State<VoiceSettingsDialog> {
     _audioProcessing = AudioProcessingConfigState.fromConfig(
       widget.initialAudioConfig,
     );
-    _audioProcessing.vadBackend = normalizedVadBackend(
-      _audioProcessing.vadBackend,
-      onnxRuntimeAvailable: widget.onnxRuntimeAvailable,
-    );
   }
 
   rust.BridgeAudioProcessingConfig _buildConfig() {
@@ -297,29 +291,14 @@ class _VoiceSettingsDialogState extends State<VoiceSettingsDialog> {
               const VoiceSubHeader('Backend'),
               SegmentedButton<rust.BridgeVadBackend>(
                 style: voiceSegmentedButtonStyle(theme),
-                segments: vadBackendSegmentsForAvailability(
-                  desktop: _isDesktopSileroVadHost,
-                  onnxRuntimeAvailable: widget.onnxRuntimeAvailable,
-                ),
+                segments: _isDesktopSileroVadHost
+                    ? desktopVadBackendSegments
+                    : vadBackendSegments,
                 selected: {_audioProcessing.vadBackend},
-                onSelectionChanged: (s) => setState(
-                  () => _audioProcessing.vadBackend = normalizedVadBackend(
-                    s.first,
-                    onnxRuntimeAvailable: widget.onnxRuntimeAvailable,
-                  ),
-                ),
+                onSelectionChanged: (s) =>
+                    setState(() => _audioProcessing.vadBackend = s.first),
               ),
               const SizedBox(height: 8),
-              if (_isDesktopSileroVadHost)
-                Text(
-                  widget.onnxRuntimeAvailable
-                      ? 'Silero gives the best quality when ONNX Runtime is installed. WebRTC works without ONNX Runtime and is the safer fallback if Linux setup is incomplete.'
-                      : 'Silero is unavailable because ONNX Runtime was not found. WebRTC is selected until libonnxruntime.so is installed or bundled.',
-                  style: theme.textTheme.bodySmall?.copyWith(
-                    color: theme.colorScheme.onSurfaceVariant,
-                  ),
-                ),
-              if (_isDesktopSileroVadHost) const SizedBox(height: 8),
 
               // ── PTT capability badge ────────────────────────────────
               if (_mode == rust.BridgeTransmitMode.ptt &&