fix(calls): the call bar shows "Call disconnected" and reconnects when sync is back (#318)

After a homeserver stall Element Call showed "Connection lost" while the
call bar still looked joined. Handle the fork's io.lotus.call_error:
show "Call disconnected" with a Reconnect button (io.lotus.reconnect),
and reconnect automatically once sync is back.

Fixes #318

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017PCb59uY3UKqDqt7B6hzd5

src/app/components/CallEmbedProvider.tsx

@@ -86,6 +86,7 @@ import { CallAvatarAnimation } from '../styles/Animations.css';
 import { webRTCSupported } from '../utils/rtc';
 import { CallsUnavailableMessage } from '../features/call/CallsUnavailable';
 import { zIndices } from '../styles/zIndex';
+import { useReconnectWhenSynced } from '../hooks/useCallError';
 
 const PIP_MIN_W = 200;
 const PIP_MIN_H = 112;
@@ -793,6 +794,7 @@ function CallUtils({ embed, joined }: { embed: CallEmbed; joined: boolean }) {
   useCallPolicyRevokedToast(embed, joined);
   useCallEndedToast(embed);
   useScreenshareNotices(embed);
+  useReconnectWhenSynced(embed.control);
   // [Gitea #43] The in-frame screenshare button follows the same room policy
   // as the host bar's (hidden where the server would refuse the share).
   const { allowScreenshare } = useRoomCallPolicy(embed.room);