fix: persist status message and timezone across reconnects

Status message: Synapse clears status_msg when a user goes offline/reconnects.
Fix by caching to localStorage and re-sending on setOnline(). The sync
effect no longer overwrites the local value with an empty server event.

Timezone: PUT /profile/{userId}/m.tz is MSC1769 (unstable) and not
supported by standard Synapse — save/load silently fails. Fix by using
Matrix account data (im.lotus.timezone) instead, which is fully
supported. Own profile falls back to account data; other users still
try the m.tz profile endpoint (for federated servers that support it).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/hooks/usePresenceUpdater.ts

@@ -16,10 +16,23 @@ export function usePresenceUpdater() {
   const lastActivityRef = useRef(0);
 
   useEffect(() => {
+    const userId = mx.getUserId();
+    const storedStatus = userId ? localStorage.getItem(`lotus-status-msg-${userId}`) ?? '' : '';
+
     const setOnline = () =>
-      mx.setPresence({ presence: 'online' }).catch(() => undefined);
+      mx.setPresence({
+        presence: 'online',
+        ...(storedStatus ? { status_msg: storedStatus } : {}),
+      }).catch(() => undefined);
     const setUnavailable = (statusMsg?: string) =>
-      mx.setPresence({ presence: 'unavailable', ...(statusMsg ? { status_msg: statusMsg } : {}) }).catch(() => undefined);
+      mx.setPresence({
+        presence: 'unavailable',
+        ...(statusMsg
+          ? { status_msg: statusMsg }
+          : storedStatus
+            ? { status_msg: storedStatus }
+            : {}),
+      }).catch(() => undefined);
     const setOffline = () =>
       mx.setPresence({ presence: 'offline', status_msg: '' }).catch(() => undefined);
 
@@ -44,7 +57,7 @@ export function usePresenceUpdater() {
     // presenceStatus === 'auto' — original activity-tracking behavior.
     const startIdleTimer = () => {
       clearTimeout(idleTimerRef.current);
-      idleTimerRef.current = window.setTimeout(() => {
+      idleTimerRef.current = setTimeout(() => {
         isIdleRef.current = true;
         setUnavailable();
       }, IDLE_TIMEOUT_MS);