fix: PiP aspect ratio matches remote video when available

- Track remote video aspect ratio in CallController via VideoFrame
  rotatedWidth/rotatedHeight
- PiP uses video's aspect ratio when remote video is active, falls
  back to 9:16 portrait for audio-only calls
- Observe isRemoteVideoActive to update PiP params when video
  starts/stops during a call

https://claude.ai/code/session_01Ak5tTkujpjNG1r5ASuPipZ

amethyst/src/main/java/com/vitorpamplona/amethyst/service/call/CallController.kt

@@ -82,11 +82,18 @@ class CallController(
     // Remote video frame monitoring — detects when peer stops sending video
     private val _isRemoteVideoActive = MutableStateFlow(false)
     val isRemoteVideoActive: StateFlow<Boolean> = _isRemoteVideoActive.asStateFlow()
+    private val _remoteVideoAspectRatio = MutableStateFlow<Float?>(null)
+    val remoteVideoAspectRatio: StateFlow<Float?> = _remoteVideoAspectRatio.asStateFlow()
     private val lastRemoteFrameTimeMs = AtomicLong(0L)
     private var remoteVideoMonitorJob: kotlinx.coroutines.Job? = null
     private val remoteFrameSink =
-        VideoSink { _: VideoFrame ->
+        VideoSink { frame: VideoFrame ->
             lastRemoteFrameTimeMs.set(System.currentTimeMillis())
+            val w = frame.rotatedWidth
+            val h = frame.rotatedHeight
+            if (w > 0 && h > 0) {
+                _remoteVideoAspectRatio.value = w.toFloat() / h.toFloat()
+            }
         }
 
     // Audio/video toggle state (UI concerns, not domain state)
@@ -358,6 +365,7 @@ class CallController(
         _isAudioMuted.value = false
         _isVideoEnabled.value = false
         _isRemoteVideoActive.value = false
+        _remoteVideoAspectRatio.value = null
         videoPausedByProximity = false
         webRtcSession?.dispose()
         webRtcSession = null

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/call/CallActivity.kt

@@ -35,6 +35,7 @@ import androidx.activity.compose.setContent
 import androidx.activity.enableEdgeToEdge
 import androidx.appcompat.app.AppCompatActivity
 import androidx.compose.runtime.mutableStateOf
+import androidx.lifecycle.lifecycleScope
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.commons.call.CallState
 import com.vitorpamplona.amethyst.ui.theme.AmethystTheme
@@ -79,6 +80,7 @@ class CallActivity : AppCompatActivity() {
         }
 
         registerPipReceiver()
+        observeVideoStateForPip(callController)
 
         setContent {
             AmethystTheme {
@@ -140,6 +142,15 @@ class CallActivity : AppCompatActivity() {
         super.onDestroy()
     }
 
+    private fun observeVideoStateForPip(controller: com.vitorpamplona.amethyst.service.call.CallController?) {
+        controller ?: return
+        lifecycleScope.launch {
+            controller.isRemoteVideoActive.collect {
+                updatePipParams()
+            }
+        }
+    }
+
     private fun enterPipIfActive() {
         if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) return
         val callManager = ActiveCallHolder.callManager ?: return
@@ -168,10 +179,11 @@ class CallActivity : AppCompatActivity() {
     }
 
     private fun buildPipParams(): PictureInPictureParams {
+        val aspectRatio = computePipAspectRatio()
         val builder =
             PictureInPictureParams
                 .Builder()
-                .setAspectRatio(Rational(9, 16))
+                .setAspectRatio(aspectRatio)
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             builder.setActions(buildPipActions())
@@ -180,6 +192,22 @@ class CallActivity : AppCompatActivity() {
         return builder.build()
     }
 
+    private fun computePipAspectRatio(): Rational {
+        val controller = ActiveCallHolder.callController ?: return Rational(9, 16)
+        val isVideoActive = controller.isRemoteVideoActive.value
+        val videoRatio = controller.remoteVideoAspectRatio.value
+
+        if (isVideoActive && videoRatio != null && videoRatio > 0f) {
+            // Clamp to Android's allowed PiP range (roughly 1:2.39 to 2.39:1)
+            val clamped = videoRatio.coerceIn(0.42f, 2.39f)
+            val num = (clamped * 1000).toInt()
+            return Rational(num, 1000)
+        }
+
+        // No active video — use portrait ratio
+        return Rational(9, 16)
+    }
+
     private fun buildPipActions(): List<RemoteAction> {
         val actions = mutableListOf<RemoteAction>()