- Added `BackToPerMethodId` constant and updated validation rules in `CloseWorkflowCommandValidator`.
- Refactored `GetWorkflowsQueryHandler` for simpler `hasListingData` logic.
- Replaced strongly-typed properties with `JsonElement` in `ContractsSourceBlock` and `FerdinandSourceBlock`.
- Updated `WorkflowListingReadModel` to use smaller data types for efficiency.
- Refactored `WorkflowRepository` to use JSON-based data retrieval and parsing.
- Introduced `MetaOnlyResponse` and `WorkflowsResponse` for consistent API responses.
- Updated `DocumentsController` and `WorkflowsController` to use new response types.
- Added `ApiKeyAuthMiddleware` for API key validation and integrated it into the middleware pipeline.
- Refactored `ExceptionHandlingMiddleware` to use `MetaOnlyResponse` for error handling.
- Performed general cleanup and modernization for improved readability and maintainability.
