fix: remote video stuck on 'waiting' — widget never rebuilt after connect

_RemoteVideoView watched liveKitServiceProvider which returns the same
keepAlive instance. When activeRoom was set after connecting, Riverpod
didn't detect the field change so the widget stayed on the null path.

Fix: also watch callControllerProvider — when state transitions from
Connecting to Active, the widget rebuilds and finds activeRoom non-null,
then ListenableBuilder takes over for participant/track changes.

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

lib/features/calls/presentation/call_screen.dart

@@ -109,11 +109,15 @@ class _CallScreenState extends ConsumerState<CallScreen> {
 
 /// Listens to the LiveKit Room's ChangeNotifier so it rebuilds when
 /// remote participants join/leave or publish/unpublish tracks.
+/// Also watches callControllerProvider so it rebuilds when the call state
+/// transitions (connecting → active) — that's when activeRoom becomes non-null.
 class _RemoteVideoView extends ConsumerWidget {
   const _RemoteVideoView();
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
+    // Watch call state to trigger rebuild when call connects.
+    ref.watch(callControllerProvider);
     final room = ref.watch(liveKitServiceProvider).activeRoom;
     if (room == null) {
       return const _NoVideoPlaceholder();
@@ -154,6 +158,7 @@ class _LocalVideoPip extends ConsumerWidget {
 
   @override
   Widget build(BuildContext context, WidgetRef ref) {
+    ref.watch(callControllerProvider); // rebuild when call state changes
     final room = ref.watch(liveKitServiceProvider).activeRoom;
     if (room == null) return const SizedBox.shrink();