Add user repos API endpoint and update DashboardApp to use it
Backend:
- Add GET /api/user/repos endpoint in router.go:63
- Add GetUserRepos handler in auth.go:327
Frontend:
- Add UserRepo type to api.ts
- Add getUserRepos API function to auth.ts
- Add useUserRepos hook to useAuth.ts
- Update DashboardApp to:
- Fetch user repos from API
- Use repos from user_repos table as fallback
- Load most recent repo automatically on login
This ensures the dashboard loads the user's most recently used repo
from the user_repos table after login, not just from URL params.