fix Live Call: route audio to speaker with proper communication device API

MODE_IN_COMMUNICATION routes to earpiece by default — no sound on speaker.
The deprecated isSpeakerphoneOn doesn't work on Android 12+.

Fix: enterCallMode()/exitCallMode() lifecycle — sets MODE_IN_COMMUNICATION
+ setCommunicationDevice(SPEAKER) on API 31+ (S25 Ultra = Android 15).
Called BEFORE AudioTrack creation so the routing is active when playback
starts. exitCallMode() restores previous audio mode on call end.

app/src/main/java/dev/kaizen/app/live/AudioPipeline.kt

@@ -62,6 +62,35 @@ class AudioPipeline(private val context: Context) {
     @Volatile private var ducking = false
     @Volatile private var capturing = false
 
+    // ─── Audio Mode ───────────────────────────────────────────────────────
+
+    fun enterCallMode() {
+        previousAudioMode = audioManager.mode
+        audioManager.mode = AudioManager.MODE_IN_COMMUNICATION
+
+        if (android.os.Build.VERSION.SDK_INT >= 31) {
+            val speaker = audioManager.availableCommunicationDevices
+                .firstOrNull { it.type == android.media.AudioDeviceInfo.TYPE_BUILTIN_SPEAKER }
+            if (speaker != null) {
+                audioManager.setCommunicationDevice(speaker)
+                Log.i(TAG, "Communication device → speaker")
+            }
+        } else {
+            @Suppress("DEPRECATION")
+            audioManager.isSpeakerphoneOn = true
+        }
+    }
+
+    fun exitCallMode() {
+        if (android.os.Build.VERSION.SDK_INT >= 31) {
+            audioManager.clearCommunicationDevice()
+        } else {
+            @Suppress("DEPRECATION")
+            audioManager.isSpeakerphoneOn = false
+        }
+        audioManager.mode = previousAudioMode
+    }
+
     // ─── Capture ──────────────────────────────────────────────────────────
 
     fun startCapture(scope: CoroutineScope): Boolean {
@@ -92,11 +121,6 @@ class AudioPipeline(private val context: Context) {
 
         recorder = rec
 
-        previousAudioMode = audioManager.mode
-        audioManager.mode = AudioManager.MODE_IN_COMMUNICATION
-        @Suppress("DEPRECATION")
-        audioManager.isSpeakerphoneOn = true
-
         if (AcousticEchoCanceler.isAvailable()) {
             try {
                 aec = AcousticEchoCanceler.create(rec.audioSessionId)
@@ -147,7 +171,6 @@ class AudioPipeline(private val context: Context) {
         aec = null
         recorder?.release()
         recorder = null
-        audioManager.mode = previousAudioMode
     }
 
     // ─── Playback ─────────────────────────────────────────────────────────
@@ -220,6 +243,7 @@ class AudioPipeline(private val context: Context) {
     fun release() {
         stopCapture()
         stopPlayback()
+        exitCallMode()
     }
 
     // ─── Helpers ──────────────────────────────────────────────────────────

app/src/main/java/dev/kaizen/app/live/LiveCallService.kt

@@ -168,6 +168,7 @@ class LiveCallService : Service() {
                 connectTimeoutJob?.cancel()
                 _status.value = CallStatus.LISTENING
 
+                pipeline.enterCallMode()
                 if (!pipeline.initPlayback()) {
                     Log.e(TAG, "Playback init failed")
                 }