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/useExtendedProfile.ts

@@ -13,6 +13,7 @@ export const useExtendedProfile = (userId: string): ExtendedProfile => {
 
   useEffect(() => {
     let cancelled = false;
+    const myUserId = mx.getUserId();
 
     const fetchField = async <T extends Record<string, string>>(
       field: string,
@@ -28,14 +29,32 @@ export const useExtendedProfile = (userId: string): ExtendedProfile => {
       }
     };
 
-    Promise.all([
-      fetchField<{ 'm.pronouns': string }>('m.pronouns'),
-      fetchField<{ 'm.tz': string }>('m.tz'),
-    ]).then(([pronouns, timezone]) => {
+    const run = async () => {
+      const [pronouns, tzFromProfile] = await Promise.all([
+        fetchField<{ 'm.pronouns': string }>('m.pronouns'),
+        fetchField<{ 'm.tz': string }>('m.tz'),
+      ]);
+
+      let timezone = tzFromProfile;
+      // Standard Synapse doesn't support m.tz — fall back to account data for own profile
+      if (!timezone && userId === myUserId) {
+        try {
+          const res = await mx.http.authedRequest<{ timezone: string }>(
+            Method.Get,
+            `/user/${encodeURIComponent(userId)}/account_data/im.lotus.timezone`,
+          );
+          timezone = res.timezone || undefined;
+        } catch {
+          // not set yet
+        }
+      }
+
       if (!cancelled) {
         setExtProfile({ pronouns: pronouns || undefined, timezone: timezone || undefined });
       }
-    });
+    };
+
+    run();
 
     return () => {
       cancelled = true;