bored - making misc changes to codura

[abdkhan-git]

Bug Fixes
Fix floating message widget flashing for unauthenticated users

• Hide floating widget on landing page (/)
• Add authChecked gate before rendering messaging widget
• Prevent unauthenticated users from seeing widget during async auth check
• Fix theme dropdown rendering behind navbar

High Priority UX / Architecture Issues

1. Fix Supabase realtime channel leak from repeated subscriptions
2. Remove isOpen dependency causing duplicate channel subscriptions
3. Avoid full conversation/message refetch on every realtime update
4. Replace any[] messaging state types with strict TypeScript interfaces
5. Add global React error boundary to prevent full app crashes
6. Lazy load Monaco editor to reduce initial bundle size
7. Replace Socket.io collaborative editing with Yjs CRDT syncing
8. Add optimistic UI updates for messaging
9. Add pagination to leaderboard queries
10. Add rate limiting to /api/problems/submit to protect Judge0 quota