Replace the bare-bones error boundary with a proper error page that:
- Renders a minimal Brackt header so users can navigate home
- Shows distinct messages and icons for 401, 403, 404, 500+ errors
- Displays a "Sign in from the home page" hint on 401 so logged-out
users know how to recover
- Hides internal details in production (stack traces dev-only)
- Uses existing dark theme Tailwind classes for visual consistency
https://claude.ai/code/session_011jv8desa5vhSkjZHSjWZiV
c8c1238963