fix: auto-reset CallManager state after call ends

CallManager now auto-resets from Ended to Idle after 2 seconds via
transitionToEnded(). Previously reset() was called from a
LaunchedEffect in CallScreen which could be cancelled when the
composable was disposed via popBack(), leaving the state stuck at
Ended and silently dropping subsequent incoming calls.

Also: CallController now observes CallManager state and auto-cleans
up the WebRTC session when a call ends (handles peer hangup case).

https://claude.ai/code/session_017hZm7yu7CzmcQgZGSaqSXS

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

@@ -48,6 +48,16 @@ class CallController(
     private var currentCallId: String? = null
     private var currentPeerPubKey: HexKey? = null
 
+    init {
+        scope.launch {
+            callManager.state.collect { state ->
+                if (state is CallState.Ended && webRtcSession != null) {
+                    cleanup()
+                }
+            }
+        }
+    }
+
     fun initiateCall(
         peerPubKey: HexKey,
         callType: CallType,

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

@@ -119,11 +119,6 @@ fun CallScreen(
         }
 
         is CallState.Ended -> {
-            LaunchedEffect(Unit) {
-                delay(2000)
-                callManager.reset()
-                onCallEnded()
-            }
             CallInProgressUI(
                 peerPubKey = state.peerPubKey,
                 statusText = "Call ended",

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/call/CallManager.kt

@@ -55,9 +55,11 @@ class CallManager(
     var onIceCandidateReceived: ((CallIceCandidateEvent) -> Unit)? = null
 
     private var timeoutJob: Job? = null
+    private var resetJob: Job? = null
 
     companion object {
         const val CALL_TIMEOUT_MS = 60_000L // 60 seconds ringing timeout
+        const val ENDED_DISPLAY_MS = 2_000L // show "call ended" briefly before resetting
     }
 
     suspend fun initiateCall(
@@ -106,8 +108,7 @@ class CallManager(
         if (current !is CallState.IncomingCall) return
 
         val result = factory.createReject(current.callerPubKey, current.callId, signer = signer)
-        _state.value = CallState.Ended(current.callId, current.callerPubKey, EndReason.REJECTED)
-        cancelTimeout()
+        transitionToEnded(current.callId, current.callerPubKey, EndReason.REJECTED)
         publishEvent(result.wrap)
     }
 
@@ -126,8 +127,7 @@ class CallManager(
         if (current !is CallState.Offering) return
         if (event.callId() != current.callId) return
 
-        _state.value = CallState.Ended(current.callId, current.peerPubKey, EndReason.PEER_REJECTED)
-        cancelTimeout()
+        transitionToEnded(current.callId, current.peerPubKey, EndReason.PEER_REJECTED)
     }
 
     fun onIceCandidate(event: CallIceCandidateEvent) {
@@ -172,8 +172,7 @@ class CallManager(
         }
 
         val result = factory.createHangup(peerPubKey, callId, signer = signer)
-        _state.value = CallState.Ended(callId, peerPubKey, EndReason.HANGUP)
-        cancelTimeout()
+        transitionToEnded(callId, peerPubKey, EndReason.HANGUP)
         publishEvent(result.wrap)
     }
 
@@ -191,8 +190,7 @@ class CallManager(
         if (callId != currentCallId) return
 
         val peerPubKey = event.pubKey
-        _state.value = CallState.Ended(callId, peerPubKey, EndReason.PEER_HANGUP)
-        cancelTimeout()
+        transitionToEnded(callId, peerPubKey, EndReason.PEER_HANGUP)
     }
 
     fun onSignalingEvent(event: Event) {
@@ -229,6 +227,25 @@ class CallManager(
     fun reset() {
         _state.value = CallState.Idle
         cancelTimeout()
+        resetJob?.cancel()
+        resetJob = null
+    }
+
+    private fun transitionToEnded(
+        callId: String,
+        peerPubKey: HexKey,
+        reason: EndReason,
+    ) {
+        _state.value = CallState.Ended(callId, peerPubKey, reason)
+        cancelTimeout()
+        resetJob?.cancel()
+        resetJob =
+            scope.launch {
+                delay(ENDED_DISPLAY_MS)
+                if (_state.value is CallState.Ended) {
+                    _state.value = CallState.Idle
+                }
+            }
     }
 
     private fun startTimeout(callId: String) {
@@ -250,7 +267,7 @@ class CallManager(
                             is CallState.IncomingCall -> current.callerPubKey
                             else -> return@launch
                         }
-                    _state.value = CallState.Ended(callId, peerPubKey, EndReason.TIMEOUT)
+                    transitionToEnded(callId, peerPubKey, EndReason.TIMEOUT)
                 }
             }
     }