feat: Remind Me Later, mobile bookmarks, bug fixes, and doc cleanup

Features:
- Remind Me Later: message context menu item opens a preset time picker
  (20 min / 1 hr / 3 hr / tomorrow 9am); reminders persist to Matrix
  account data (io.lotus.reminders); ReminderMonitor fires a Lotus Toast
  when due, checks every 30s and on tab focus
- Mobile Bookmarks: BookmarksPanel now renders on all screen sizes;
  passes isMobile prop for full-screen absolute overlay on mobile

Bug fixes:
- usePan.ts: memory leak from stale closure in document listener cleanup
- EventReaders.tsx: replace hardcoded hex colors with TDS CSS variables
- CallControls.tsx: replace hardcoded hex colors with TDS CSS variables
- CustomHtml.css.ts: replace hardcoded yellow/black highlight with theme tokens

Docs:
- LOTUS_TODO.md: restore deleted content (Confirmed facts table, Pending
  Audits, P5-30 completed status, full feature descriptions), keep new
  additions (P4-7/8/9, P5-41–57, Implementation Reference), eliminate
  duplicate sections
- LOTUS_BUGS.md: merge RESILIENCE_AUDIT.md findings into Architectural &
  Resilience Audit table; delete RESILIENCE_AUDIT.md
- Remove stale LOTUS_DENOISE_ENGINEERING_REVIEW.md and LOTUS_TODO_REFERENCE.md

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

src/app/pages/client/ClientNonUIFeatures.tsx

@@ -36,6 +36,7 @@ import { useMediaAuthentication } from '../../hooks/useMediaAuthentication';
 import { usePresenceUpdater } from '../../hooks/usePresenceUpdater';
 import { useDeepLinkNavigate } from '../../hooks/useDeepLinkNavigate';
 import { toastQueueAtom } from '../../state/toast';
+import { useReminders } from '../../hooks/useReminders';
 
 function isInQuietHours(start: string, end: string): boolean {
   const now = new Date();
@@ -382,6 +383,50 @@ function DeepLinkNavigator() {
   return null;
 }
 
+function ReminderMonitor() {
+  const mx = useMatrixClient();
+  const { reminders, removeReminder } = useReminders();
+  const setToast = useSetAtom(toastQueueAtom);
+  const mDirects = useAtomValue(mDirectAtom);
+  const firedRef = useRef<Set<string>>(new Set());
+
+  useEffect(() => {
+    const check = () => {
+      const now = Date.now();
+      reminders.forEach((r) => {
+        const key = `${r.eventId}-${r.timestamp}`;
+        if (r.timestamp <= now && !firedRef.current.has(key)) {
+          firedRef.current.add(key);
+          const room = mx.getRoom(r.roomId);
+          const hashPath = mDirects.has(r.roomId)
+            ? getDirectRoomPath(r.roomId)
+            : getHomeRoomPath(r.roomId);
+          setToast({
+            id: `reminder-${key}`,
+            displayName: 'Reminder',
+            body: r.message,
+            roomName: room?.name ?? 'Unknown Room',
+            roomId: r.roomId,
+            hashPath,
+          });
+          removeReminder(r.eventId, r.timestamp);
+        }
+      });
+    };
+
+    check();
+    const interval = setInterval(check, 30_000);
+    const onVisible = () => { if (document.visibilityState === 'visible') check(); };
+    document.addEventListener('visibilitychange', onVisible);
+    return () => {
+      clearInterval(interval);
+      document.removeEventListener('visibilitychange', onVisible);
+    };
+  }, [mx, reminders, setToast, removeReminder, mDirects]);
+
+  return null;
+}
+
 function LotusDenoiseFeature() {
   const setToast = useSetAtom(toastQueueAtom);
 
@@ -417,6 +462,7 @@ export function ClientNonUIFeatures({ children }: ClientNonUIFeaturesProps) {
       <PresenceUpdater />
       <InviteNotifications />
       <MessageNotifications />
+      <ReminderMonitor />
       <LotusDenoiseFeature />
       <DeepLinkNavigator />
       {children}