test: add comprehensive test coverage and improve code quality

- 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)

internal/api/middleware/cors.go

@@ -10,7 +10,7 @@ import (
 )
 
 var corsConfig = config.CORSConfig{
-	AllowedOrigins: []string{"*"},
+	AllowedOrigins:   []string{"*"},
 	AllowCredentials: true,
 }