fix(call): answering an incoming call honours cameraOnJoin and mic/sound prefs

handleAnswer hard-coded { microphone: true, video, sound: true }, so
pressing Answer on a video call published the camera even with the
"Join with Camera On" setting off (the default) and ignored a persisted
muted/deafened preference. Build the answer prefs the same way every other
join path does; PTT's forceAudioOff still applies downstream.

Fixes #8

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/components/CallEmbedProvider.tsx

@@ -58,6 +58,7 @@ import { ExitFullscreenIcon, FullscreenIcon } from '../features/call/Controls';
 import { useTheme, ThemeKind } from '../hooks/useTheme';
 import { useReducedMotion } from '../hooks/useReducedMotion';
 import { useSetting } from '../state/hooks/settings';
+import { useCallPreferences } from '../state/hooks/callPreferences';
 import { settingsAtom } from '../state/settings';
 import { getStateEvent, getStateEvents, getMemberName } from '../utils/room';
 import { StateEvent } from '../../types/matrix/room';
@@ -410,6 +411,8 @@ function IncomingCallListener({ callEmbed, joined }: IncomingCallListenerProps)
   const [callInfo, setCallInfo] = useState<IncomingCallInfo>();
   const dm = callInfo ? directs.has(callInfo.room.roomId) : false;
   const startCall = useCallStart(dm);
+  const { microphone, sound } = useCallPreferences();
+  const [cameraOnJoin] = useSetting(settingsAtom, 'cameraOnJoin');
 
   // C-L6: handleTimelineEvent awaits decryption before calling setState; guard
   // against the component unmounting during that await.
@@ -566,11 +569,15 @@ function IncomingCallListener({ callEmbed, joined }: IncomingCallListenerProps)
 
   const handleAnswer = useCallback(
     (room: Room, video: boolean) => {
-      startCall(room, { microphone: true, video, sound: true });
+      // Honour cameraOnJoin and the persisted mic/sound preferences instead of
+      // forcing camera+mic+sound on — every other join path does this, and
+      // Answer was skipping it, publishing the camera with no prescreen.
+      // (PTT's forceAudioOff is applied downstream inside useCallStart.)
+      startCall(room, { microphone, video: cameraOnJoin && video, sound });
       setCallInfo(undefined);
       navigateRoom(room.roomId);
     },
-    [startCall, navigateRoom],
+    [startCall, navigateRoom, microphone, sound, cameraOnJoin],
   );
 
   if (!callInfo) return null;