1db41a5c62
This commit introduces a comprehensive refactoring and stabilization of the core module, establishing a robust and well-tested foundation (Shared Kernel) for all other services. The module has been thoroughly analyzed, cleaned up, and equipped with a professional-grade test suite. Architectural Refinements: - Slimmed down `core-domain` to be a true, minimal Shared Kernel by removing all domain-specific enums (`PferdeGeschlechtE`, `SparteE`, etc.). This enforces loose coupling between feature modules. - The only remaining enum is `DatenQuelleE`, which is a cross-cutting concern. Code Refactoring & Improvements: - Refactored the configuration loading by introducing a `ConfigLoader` class. This decouples the `AppConfig` data classes from the loading mechanism, significantly improving the testability of components that rely on configuration. - Unified the previously duplicated `ValidationResult` and `ValidationError` classes into a single, serializable source of truth, ensuring consistent error reporting across all APIs. Testing Enhancements: - Introduced a comprehensive test suite for the core module, bringing it to a production-ready quality standard. - Implemented the "gold standard" for database testing by replacing the previous H2 approach with **Testcontainers**. The `DatabaseFactory` is now tested against a real, ephemeral PostgreSQL container, guaranteeing 100% production parity. - Added robust unit and integration tests for critical components, including the new `ConfigLoader`, all custom `Serializers`, and the `ApiResponse` logic. - Fixed all compilation and runtime errors in the test suite, resulting in a successful `./gradlew clean build`.