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/plugins/call/CallEmbed.ts

@@ -450,6 +450,12 @@ export class CallEmbed {
         this.control.onControlsState((evt.detail as { data?: unknown } | undefined)?.data);
       }),
     );
+    // [Gitea #318] The fork's error page ("Connection lost") is up / cleared.
+    this.disposables.push(
+      this.listenAction('io.lotus.call_error', (evt) => {
+        this.control.onCallError((evt.detail as { data?: unknown } | undefined)?.data);
+      }),
+    );
     // [Gitea #43] PTT / deafen keys pressed while focus is inside the frame.
     this.disposables.push(
       this.listenAction('io.lotus.hotkey', (evt) => {