Introduced DTOs for request and response to handle Swiss QR Code extraction from PDF documents. Implemented `ExtractSwissQrCodeHandler` to process the extraction using `ISwissQrCodeProcessor`. Added validation for the query with `ExtractSwissQrCodeValidator`. Developed unit tests to ensure correct behavior for successful and failure scenarios.
Updated PHASENPLAN and ROADMAP to reflect progress on Feature 1 - ValidatePDF (75% complete). Marked Step 1.1 as completed, including MediatR setup, pipeline behaviors (`ValidationBehavior`, `LoggingBehavior`), ValidatePDF feature (Query, Handler, Validator), and DTOs.
Added `DependencyInjection.cs` for Application Layer DI configuration. Introduced `LoggingBehavior` and `ValidationBehavior` for MediatR pipelines. Implemented `ValidatePdfHandler`, `ValidatePdfQuery`, and `ValidatePdfValidator`.
Created DTOs (`ValidatePdfRequest`, `ValidatePdfResponse`) for the ValidatePDF feature. Added unit tests for `ValidatePdfHandler` to verify metadata handling and exception propagation.
Removed unused folder references in `DocumentOperator.Application.csproj`.
