feat: auto-clear status after configurable duration

Adds an 'Auto-clear after' dropdown to the Status Message settings tile
with options: Never / 30 min / 1 hr / 4 hr / 8 hr / Until midnight /
1 day / 7 days.

How it works:
- On save, stores the expiry timestamp in localStorage keyed by userId
  (lotus-status-expiry-<userId>) and sets expiryTs state
- A single useEffect on expiryTs drives the timer — re-saving cancels
  the previous timer cleanly via useEffect cleanup
- On mount, reads stored expiry from localStorage so auto-clear
  survives page reloads (fires immediately if already expired)
- Manual Clear Status also removes the stored expiry and cancels any
  active timer

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

src/app/features/settings/account/Profile.tsx

@@ -319,19 +319,68 @@ function ProfileDisplayName({ profile, userId }: ProfileProps) {
   );
 }
 
+const STATUS_EXPIRY_KEY = (id: string) => `lotus-status-expiry-${id}`;
+
+const CLEAR_AFTER_OPTIONS = [
+  { label: 'Never', value: '0' },
+  { label: '30 minutes', value: String(30 * 60 * 1000) },
+  { label: '1 hour', value: String(60 * 60 * 1000) },
+  { label: '4 hours', value: String(4 * 60 * 60 * 1000) },
+  { label: '8 hours', value: String(8 * 60 * 60 * 1000) },
+  { label: 'Until midnight', value: 'today' },
+  { label: '1 day', value: String(24 * 60 * 60 * 1000) },
+  { label: '7 days', value: String(7 * 24 * 60 * 60 * 1000) },
+];
+
+function getMsFromOption(value: string): number {
+  if (value === '0') return 0;
+  if (value === 'today') {
+    const eod = new Date();
+    eod.setHours(23, 59, 59, 999);
+    return eod.getTime() - Date.now();
+  }
+  return parseInt(value, 10);
+}
+
 function ProfileStatus() {
   const mx = useMatrixClient();
   const userId = mx.getUserId()!;
   const presence = useUserPresence(userId);
 
   const [statusMsg, setStatusMsg] = useState<string>(presence?.status ?? '');
+  const [clearAfter, setClearAfter] = useState('0');
   const [emojiAnchor, setEmojiAnchor] = useState<RectCords>();
   const inputRef = useRef<HTMLInputElement>(null);
 
+  // Initialise expiry from localStorage so timer survives page reload
+  const [expiryTs, setExpiryTs] = useState<number>(() => {
+    const stored = localStorage.getItem(STATUS_EXPIRY_KEY(userId));
+    return stored ? parseInt(stored, 10) : 0;
+  });
+
+  // Sync input when another device changes the status
   useEffect(() => {
     setStatusMsg(presence?.status ?? '');
   }, [presence?.status]);
 
+  // Drive the auto-clear timer off expiryTs so re-saving cancels the old timer
+  useEffect(() => {
+    if (!expiryTs) return undefined;
+    const remaining = expiryTs - Date.now();
+    if (remaining <= 0) {
+      localStorage.removeItem(STATUS_EXPIRY_KEY(userId));
+      setExpiryTs(0);
+      mx.setPresence({ presence: 'online', status_msg: '' });
+      return undefined;
+    }
+    const timer = window.setTimeout(() => {
+      localStorage.removeItem(STATUS_EXPIRY_KEY(userId));
+      setExpiryTs(0);
+      mx.setPresence({ presence: 'online', status_msg: '' });
+    }, remaining);
+    return () => clearTimeout(timer);
+  }, [expiryTs, userId, mx]);
+
   const [saveState, saveStatus] = useAsyncCallback(
     useCallback(
       (msg: string) =>
@@ -352,7 +401,6 @@ function ProfileStatus() {
         const end = input.selectionEnd ?? statusMsg.length;
         const next = statusMsg.slice(0, start) + unicode + statusMsg.slice(end);
         setStatusMsg(next);
-        // restore cursor after emoji insertion
         requestAnimationFrame(() => {
           input.focus();
           input.setSelectionRange(start + unicode.length, start + unicode.length);
@@ -372,15 +420,25 @@ function ProfileStatus() {
   const handleSubmit: FormEventHandler<HTMLFormElement> = (evt) => {
     evt.preventDefault();
     if (saving) return;
-    saveStatus(statusMsg.trim());
+    const msg = statusMsg.trim();
+    saveStatus(msg);
+
+    const delayMs = getMsFromOption(clearAfter);
+    if (msg && delayMs > 0) {
+      const ts = Date.now() + delayMs;
+      localStorage.setItem(STATUS_EXPIRY_KEY(userId), String(ts));
+      setExpiryTs(ts);
+    } else {
+      localStorage.removeItem(STATUS_EXPIRY_KEY(userId));
+      setExpiryTs(0);
+    }
   };
 
   const handleClear = () => {
     setStatusMsg('');
-    mx.setPresence({
-      presence: 'online',
-      status_msg: '',
-    });
+    localStorage.removeItem(STATUS_EXPIRY_KEY(userId));
+    setExpiryTs(0);
+    mx.setPresence({ presence: 'online', status_msg: '' });
   };
 
   const hasChanges = statusMsg !== (presence?.status ?? '');
@@ -460,6 +518,32 @@ function ProfileStatus() {
             <Text size="B400">Save</Text>
           </Button>
         </Box>
+        <Box alignItems="Center" gap="200">
+          <Text size="T200" style={{ opacity: 0.6, whiteSpace: 'nowrap', flexShrink: 0 }}>
+            Auto-clear after:
+          </Text>
+          <select
+            value={clearAfter}
+            onChange={(e) => setClearAfter(e.target.value)}
+            aria-label="Auto-clear status after"
+            style={{
+              background: 'var(--bg-surface-variant)',
+              border: `1px solid var(--border-surface-variant)`,
+              borderRadius: config.radii.R300,
+              color: 'inherit',
+              fontSize: '0.82rem',
+              padding: `${config.space.S100} ${config.space.S200}`,
+              cursor: 'pointer',
+              outline: 'none',
+            }}
+          >
+            {CLEAR_AFTER_OPTIONS.map((opt) => (
+              <option key={opt.value} value={opt.value}>
+                {opt.label}
+              </option>
+            ))}
+          </select>
+        </Box>
         {(presence?.status || statusMsg) && (
           <Button
             size="300"