fix(schedule): load scheduled messages from the server; offer to cancel them at logout (#322)

The tray only knew what this browser had scheduled (localStorage), but
Synapse lists every pending one via MSC4140 GET /delayed_events. Load it
when the tray mounts and on window focus (localStorage stays as a first-
paint cache), keeping only non-state m.room.message events. Logout now
says "N scheduled messages still send after you log out" and offers to
cancel them.

Fixes #322

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

src/app/features/room/ScheduledMessagesTray.tsx

@@ -4,7 +4,12 @@ import { IContent } from 'matrix-js-sdk';
 import { Box, Button, Icon, IconButton, Icons, Text, color, config } from 'folds';
 import { useMatrixClient } from '../../hooks/useMatrixClient';
 import { scheduledMessagesAtom, ScheduledMessage } from '../../state/scheduledMessages';
-import { cancelScheduledMessage, sendScheduledMessageNow } from '../../utils/scheduledMessages';
+import {
+  cancelScheduledMessage,
+  fetchScheduledMessages,
+  groupScheduledByRoom,
+  sendScheduledMessageNow,
+} from '../../utils/scheduledMessages';
 import { ScheduleMessageModal } from './ScheduleMessageModal';
 import { useTimestampFormatter } from '../../hooks/useTimestampFormatter';
 import { formatFriendlyDateTime } from '../../utils/datetimeInput';
@@ -26,6 +31,26 @@ export function ScheduledMessagesTray({ roomId }: ScheduledMessagesTrayProps) {
 
   const messages = useMemo(() => scheduledMessages.get(roomId) ?? [], [scheduledMessages, roomId]);
 
+  // [Gitea #322] The server is the source of truth: messages scheduled on
+  // another device (or before a logout) show up here and can be cancelled.
+  // localStorage is only a cache for the first paint; on error we keep it.
+  useEffect(() => {
+    let alive = true;
+    const load = () => {
+      fetchScheduledMessages(mx)
+        .then((list) => {
+          if (alive) setScheduledMessages(groupScheduledByRoom(list));
+        })
+        .catch(() => undefined);
+    };
+    load();
+    window.addEventListener('focus', load);
+    return () => {
+      alive = false;
+      window.removeEventListener('focus', load);
+    };
+  }, [mx, roomId, setScheduledMessages]);
+
   // Remove scheduled messages whose time has passed
   useEffect(() => {
     if (messages.length === 0) return undefined;