P1-02: OAuth ExchangeCode and GetUserInfo now accept context parameter
to properly propagate request context to HTTP calls
P1-16: AuthProvider isAuthenticated now uses single source of truth
(effectiveUser !== null) instead of double-checking both
React state and module-level function
- Add new test files for auth, service, and handler modules
- Improve test organization and coverage
- Refactor code for better maintainability
- Add captcha, settings, stats, and theme handler tests
- Add auth module tests (CAS, OAuth, password, SSO, state)
- Add service layer tests for auth, export, permissions, roles
- All Go tests pass (exit code 0)
- All frontend tests pass (325 tests in 59 files)
