fix(calls): warn before unload during a joined call

Register beforeunload while joined so Ctrl+R / tab close prompts instead
of silently dropping the call. Also removes the setPipMode effect (#59).

Fixes #58

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/components/CallEmbedProvider.tsx

@@ -631,6 +631,22 @@ function CallUtils({ embed, joined }: { embed: CallEmbed; joined: boolean }) {
     }, [setCallEmbed]),
   );
 
+  // [Gitea #58] Warn before an accidental tab close/reload drops the user out
+  // of a live call. Only armed while actually joined, and torn down on
+  // hangup/dispose since this effect re-runs when `joined` flips back to false.
+  useEffect(() => {
+    if (!joined) return undefined;
+    const onBeforeUnload = (event: BeforeUnloadEvent) => {
+      event.preventDefault();
+      // Legacy browsers require returnValue to be set to show the prompt.
+      event.returnValue = '';
+    };
+    window.addEventListener('beforeunload', onBeforeUnload);
+    return () => {
+      window.removeEventListener('beforeunload', onBeforeUnload);
+    };
+  }, [joined]);
+
   return null;
 }
 
@@ -735,12 +751,6 @@ export function CallEmbedProvider({ children }: CallEmbedProviderProps) {
     };
   }, []);
 
-  // Sync pip mode into CallControl so it can adjust behavior accordingly
-  useEffect(() => {
-    if (!callEmbed) return;
-    callEmbed.control.setPipMode(!!pipMode);
-  }, [pipMode, callEmbed]);
-
   // When entering pip with screenshare active (or screenshare starts while in pip),
   // enable spotlight so the screenshare fills the pip window.
   // When screenshare ends, release the spotlight we auto-enabled.