feat: presence fix, voice ringing fix, user private notes + doc updates

- usePresenceUpdater: replace stale closure with readStatus() called at
  invocation time so changing custom status in Profile Settings is never
  silently overwritten by subsequent activity events
- CallEmbedProvider: fix m.space.parent state-key lookup by switching
  getStateEvent → getStateEvents (plural); space channel voice rooms no
  longer trigger the incoming-call ring/animation
- Add useUserNotes hook (io.lotus.user_notes account data, reactive via
  useAccountDataCallback, 500-char limit, cross-device sync)
- UserRoomProfile: add UserPrivateNotes textarea with 800ms debounced
  auto-save, saving indicator, char counter when <100 chars remain;
  shown only when viewing another user's profile
- LOTUS_FEATURES.md: add Private Notes section, Status Revert fix note,
  animation improvements subsection, Seasonal Themes section
- LOTUS_BUGS.md: mark presence revert + voice ringing bugs as resolved
- README.md + landing/index.html: document all new June 2026 features

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

src/app/hooks/usePresenceUpdater.ts

@@ -17,26 +17,34 @@ export function usePresenceUpdater() {
 
   useEffect(() => {
     const userId = mx.getUserId();
-    const storedStatus = userId ? (localStorage.getItem(`lotus-status-msg-${userId}`) ?? '') : '';
 
-    const setOnline = () =>
-      mx
+    // Read status from localStorage at call time so manual updates from the
+    // Profile settings are never overwritten by a stale closure value.
+    const readStatus = () =>
+      userId ? (localStorage.getItem(`lotus-status-msg-${userId}`) ?? '') : '';
+
+    const setOnline = () => {
+      const status = readStatus();
+      return mx
         .setPresence({
           presence: 'online',
-          ...(storedStatus ? { status_msg: storedStatus } : {}),
+          ...(status ? { status_msg: status } : {}),
         })
         .catch(() => undefined);
-    const setUnavailable = (statusMsg?: string) =>
-      mx
+    };
+    const setUnavailable = (statusMsg?: string) => {
+      const status = readStatus();
+      return mx
         .setPresence({
           presence: 'unavailable',
           ...(statusMsg
             ? { status_msg: statusMsg }
-            : storedStatus
-              ? { status_msg: storedStatus }
+            : status
+              ? { status_msg: status }
               : {}),
         })
         .catch(() => undefined);
+    };
     const setOffline = () =>
       mx.setPresence({ presence: 'offline', status_msg: '' }).catch(() => undefined);