fix(calls): no "the shared window was closed" toast when an admin turns sharing off (#297)

When a room admin turned off Allow Screen Sharing, the sharer got two
toasts: the correct "turned off by a room admin" and the fork's
"ended" notice, "the shared window was closed", which was wrong. Skip
the ended notice while the room policy forbids sharing.

Fixes #297

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

src/app/hooks/useScreenshareNotices.test.ts

@@ -0,0 +1,10 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { shouldShowScreenshareNotice } from './useScreenshareNotices';
+
+test('shouldShowScreenshareNotice: no "window was closed" when an admin turned sharing off (#297)', () => {
+  assert.equal(shouldShowScreenshareNotice('ended', false), false);
+  assert.equal(shouldShowScreenshareNotice('ended', true), true);
+  assert.equal(shouldShowScreenshareNotice('no-frames', false), true);
+  assert.equal(shouldShowScreenshareNotice('alone', true), true);
+});

src/app/hooks/useScreenshareNotices.ts

@@ -1,8 +1,9 @@
-import { useEffect } from 'react';
+import { useEffect, useRef } from 'react';
 import { useSetAtom } from 'jotai';
 import { Icons } from 'folds';
 import { CallEmbed } from '../plugins/call';
 import { toastQueueAtom } from '../state/toast';
+import { useRoomCallPolicy } from './useRoomCallPolicy';
 
 export type ScreenshareNoticeKind = 'ended' | 'no-frames' | 'alone';
 
@@ -19,18 +20,32 @@ export const describeScreenshareNotice = (kind: ScreenshareNoticeKind): string |
   }
 };
 
+/** Pure: a policy-forced stop is explained by its own toast (#297). */
+export const shouldShowScreenshareNotice = (
+  kind: ScreenshareNoticeKind,
+  allowScreenshare: boolean,
+): boolean => !(kind === 'ended' && !allowScreenshare);
+
 /**
  * [Gitea EC#39] Toast the fork's io.lotus.screenshare_notice: shared window
  * closed, no frames for a while, or a long share with nobody watching.
  */
 export function useScreenshareNotices(embed: CallEmbed): void {
   const setToast = useSetAtom(toastQueueAtom);
+  // [Gitea #297] When a room admin turns screen sharing off, the share ends
+  // and the fork reports `ended` ("the shared window was closed"), which is
+  // wrong; useCallPolicyRevokedToast already says what happened.
+  const { allowScreenshare } = useRoomCallPolicy(embed.room);
+  const allowRef = useRef(allowScreenshare);
+  allowRef.current = allowScreenshare;
   useEffect(
     () =>
       embed.listenAction<{ data?: { kind?: ScreenshareNoticeKind } }>(
         'io.lotus.screenshare_notice',
         (evt) => {
-          const body = describeScreenshareNotice(evt.detail?.data?.kind as ScreenshareNoticeKind);
+          const kind = evt.detail?.data?.kind as ScreenshareNoticeKind;
+          if (!shouldShowScreenshareNotice(kind, allowRef.current)) return;
+          const body = describeScreenshareNotice(kind);
           if (!body) return;
           setToast({
             id: `screenshare-${evt.detail?.data?.kind}-${Date.now()}`,