- Removed redundant `gin.SetMode(gin.TestMode)` calls from individual test files.
- Introduced a centralized `TestMain` function in `testmain_test.go` to set the Gin mode for all tests.
- Ensured consistent test environment setup across various handler test files.
- Implement tests for feature flags coverage in `feature_flags_coverage_v2_test.go` to validate behavior with invalid persisted and environment values, as well as default settings.
- Create tests in `notification_provider_patch_coverage_test.go` to ensure correct handling of notification provider updates, including blocking type mutations for non-Discord providers.
- Add tests in `security_notifications_patch_coverage_test.go` to verify deprecated headers, handle invalid CIDR warnings, and ensure correct severity handling for security events.
- Introduce migration error handling tests in `routes_coverage_test.go` to ensure graceful handling of migration errors during registration.
- Enhance `cerberus_blockers_test.go` with tests for disabled security event notifications and error handling for dispatch failures.
- Update `router_test.go` to validate notify routing based on feature flags.
- Refactor `mail_service.go` to normalize base URLs for invites, ensuring proper handling of trailing slashes.
- Modify `notification_service_json_test.go` and `notification_service_test.go` to mock Discord validation and improve webhook testing.
- Update `proxyhost_service.go` to enhance hostname validation by parsing URLs.
- Refine `uptime_service.go` to extract ports correctly from URLs, including handling edge cases.
- Enhance frontend tests in `notifications.test.ts` and `Notifications.test.tsx` to ensure correct behavior for Discord notification providers and enforce type constraints.
