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/components/user-profile/UserRoomProfile.tsx

@@ -1,5 +1,5 @@
 import { Box, Button, config, Icon, IconButton, Icons, Spinner, Text, toRem } from 'folds';
-import React, { useCallback, useState } from 'react';
+import React, { useCallback, useEffect, useRef, useState } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { VerificationRequest } from 'matrix-js-sdk/lib/crypto-api';
 import { AsyncState, AsyncStatus, useAsync } from '../../hooks/useAsyncCallback';
@@ -32,6 +32,7 @@ import { CreatorChip } from './CreatorChip';
 import { getDirectCreatePath, withSearchParam } from '../../pages/pathUtils';
 import { DirectCreateSearchParams } from '../../pages/paths';
 import { useExtendedProfile } from '../../hooks/useExtendedProfile';
+import { useUserNotes, USER_NOTE_MAX_LENGTH } from '../../hooks/useUserNotes';
 
 type VerifyDeviceButtonProps = {
   userId: string;
@@ -207,6 +208,65 @@ function UserDeviceSessions({ userId }: UserDeviceSessionsProps) {
   );
 }
 
+function UserPrivateNotes({ userId }: { userId: string }) {
+  const { getNote, setNote } = useUserNotes();
+  const [draft, setDraft] = useState(() => getNote(userId));
+  const [saving, setSaving] = useState(false);
+  const saveTimer = useRef<ReturnType<typeof setTimeout> | undefined>(undefined);
+
+  // Sync if account data arrives after mount
+  useEffect(() => {
+    setDraft(getNote(userId));
+  }, [getNote, userId]);
+
+  const handleChange = (e: React.ChangeEvent<HTMLTextAreaElement>) => {
+    const val = e.target.value;
+    setDraft(val);
+    clearTimeout(saveTimer.current);
+    saveTimer.current = setTimeout(async () => {
+      setSaving(true);
+      await setNote(userId, val);
+      setSaving(false);
+    }, 800);
+  };
+
+  useEffect(() => () => clearTimeout(saveTimer.current), []);
+
+  const charsLeft = USER_NOTE_MAX_LENGTH - draft.length;
+
+  return (
+    <Box direction="Column" gap="200">
+      <Box justifyContent="SpaceBetween" alignItems="Center">
+        <Text size="L400">Private Note</Text>
+        <Text size="T200" style={{ opacity: 0.5 }}>
+          {saving ? 'Saving…' : charsLeft < 100 ? `${charsLeft} left` : ''}
+        </Text>
+      </Box>
+      <textarea
+        value={draft}
+        onChange={handleChange}
+        maxLength={USER_NOTE_MAX_LENGTH}
+        placeholder="Notes only visible to you…"
+        rows={3}
+        style={{
+          width: '100%',
+          resize: 'vertical',
+          background: 'var(--bg-surface-variant)',
+          color: 'inherit',
+          border: '1px solid var(--border-interactive)',
+          borderRadius: '6px',
+          padding: '8px 10px',
+          fontSize: '14px',
+          fontFamily: 'inherit',
+          lineHeight: 1.5,
+          boxSizing: 'border-box',
+          outline: 'none',
+        }}
+      />
+    </Box>
+  );
+}
+
 type UserRoomProfileProps = {
   userId: string;
 };
@@ -331,6 +391,7 @@ export function UserRoomProfile({ userId }: UserRoomProfileProps) {
           canBan={canBanUser && membership !== Membership.Ban}
         />
         {showEncryption && userId !== myUserId && <UserDeviceSessions userId={userId} />}
+        {userId !== myUserId && <UserPrivateNotes userId={userId} />}
       </Box>
     </Box>
   );