New test files:
- meta_test.go: Test meta query with different config flags
- users_test.go: Test _users admin query with/without auth, pagination
- user_test.go: Test _user admin query by ID, by email, unauthorized
- admin_session_test.go: Test _admin_session query
- verification_requests_test.go: Test _verification_requests admin query
- webhooks_test.go: Test _webhooks list and _webhook single queries
- webhook_logs_test.go: Test _webhook_logs query
- email_templates_test.go: Test _email_templates query

Edge-case tests added to existing files:
- signup_test.go: Test signup when EnableSignup=false
- login_test.go: Test login with basic auth disabled, login with revoked user
- reset_password_test.go: Test password mismatch
- update_profile_test.go: Test password change flow