feat: debug recording off by default, toggle in settings

- AudioPipeline.debugRecording defaults to false (was true)
- SettingsRepository: persist debug_recording preference
- CallViewModel: debugRecording StateFlow + setter, wired to AudioPipeline
- Only records PCM + RMS when explicitly enabled in settings

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

android/app/src/main/java/com/wzp/audio/AudioPipeline.kt

@@ -57,7 +57,7 @@ class AudioPipeline(private val context: Context) {
     /** Whether to attach hardware AEC. Must be set before start(). */
     var aecEnabled: Boolean = true
     /** Enable debug recording of PCM + RMS histogram to cache dir. */
-    var debugRecording: Boolean = true
+    var debugRecording: Boolean = false
     private var captureThread: Thread? = null
     private var playoutThread: Thread? = null
 

android/app/src/main/java/com/wzp/data/SettingsRepository.kt

@@ -28,6 +28,7 @@ class SettingsRepository(context: Context) {
         private const val KEY_PREFER_IPV6 = "prefer_ipv6"
         private const val KEY_IDENTITY_SEED = "identity_seed_hex"
         private const val KEY_AEC_ENABLED = "aec_enabled"
+        private const val KEY_DEBUG_RECORDING = "debug_recording"
         private const val KEY_RECENT_ROOMS = "recent_rooms"
         private const val TOFU_PREFIX = "tofu_"
     }
@@ -120,6 +121,11 @@ class SettingsRepository(context: Context) {
     fun saveAecEnabled(enabled: Boolean) { prefs.edit().putBoolean(KEY_AEC_ENABLED, enabled).apply() }
     fun loadAecEnabled(): Boolean = prefs.getBoolean(KEY_AEC_ENABLED, true)
 
+    // --- Debug recording ---
+
+    fun saveDebugRecording(enabled: Boolean) { prefs.edit().putBoolean(KEY_DEBUG_RECORDING, enabled).apply() }
+    fun loadDebugRecording(): Boolean = prefs.getBoolean(KEY_DEBUG_RECORDING, false)
+
     // --- Identity seed ---
 
     /**

android/app/src/main/java/com/wzp/ui/call/CallViewModel.kt

@@ -105,6 +105,9 @@ class CallViewModel : ViewModel(), WzpCallback {
     private val _aecEnabled = MutableStateFlow(true)
     val aecEnabled: StateFlow<Boolean> = _aecEnabled.asStateFlow()
 
+    private val _debugRecording = MutableStateFlow(false)
+    val debugRecording: StateFlow<Boolean> = _debugRecording.asStateFlow()
+
     /** True when a call just ended and debug report can be sent. */
     private val _debugReportAvailable = MutableStateFlow(false)
     val debugReportAvailable: StateFlow<Boolean> = _debugReportAvailable.asStateFlow()
@@ -159,6 +162,7 @@ class CallViewModel : ViewModel(), WzpCallback {
         _captureGainDb.value = s.loadCaptureGain()
         _seedHex.value = s.getOrCreateSeedHex()
         _aecEnabled.value = s.loadAecEnabled()
+        _debugRecording.value = s.loadDebugRecording()
         _recentRooms.value = s.loadRecentRooms()
     }
 
@@ -288,6 +292,11 @@ class CallViewModel : ViewModel(), WzpCallback {
         settings?.saveAecEnabled(enabled)
     }
 
+    fun setDebugRecording(enabled: Boolean) {
+        _debugRecording.value = enabled
+        settings?.saveDebugRecording(enabled)
+    }
+
     /**
      * Resolve DNS hostname to IP address on the Kotlin/Android side,
      * since Rust's DNS resolution may not work on Android.
@@ -476,6 +485,7 @@ class CallViewModel : ViewModel(), WzpCallback {
             it.playoutGainDb = _playoutGainDb.value
             it.captureGainDb = _captureGainDb.value
             it.aecEnabled = _aecEnabled.value
+            it.debugRecording = _debugRecording.value
             it.start(e)
         }
         audioRouteManager?.register()