Introduced `ZugferdController` to handle ZUGFeRD-related operations, including detection and extraction of ZUGFeRD XML from PDFs via file upload or Base64-encoded payloads. Integrated `MediatR` for query/command handling.
Added `ZugferdSettings` for configurable file names and patterns, and updated `appsettings.json` and `Program.cs` to support this configuration.
Implemented `HasZugferdQuery` and `ExtractZugferdCommand` with their respective handlers and validators. Added DTOs (`ZugferdCheckResult`, `ZugferdExtractionResult`) for operation results.
Included `ZUGFeRD-Example.pdf` for testing and integrated `Serilog.Ui.Core.Extensions` for logging.
Refactored `DevExpressPdfProcessor` to improve attachment detection:
- Changed `DetectEmbeddedFiles` return type to a tuple for better
handling of attachment presence and count.
- Enhanced logic to parse `/Names` arrays and count object references
for accurate attachment detection.
- Implemented robust search for `/EmbeddedFiles` to handle multiple
occurrences and ensure proper context validation.
Updated PHASENPLAN.md and ROADMAP.md to reflect these changes, including
the addition of fixes for attachment detection and counting logic.
Added new tests in `DevExpressPdfProcessorTests`:
- Verified detection of multiple attachments and accurate counts.
- Ensured no crashes when processing PDFs with `/EmbeddedFiles`.
Included a new test resource (`pdfWithMoreThanOneAttachment.pdf`) for
validating multiple attachment scenarios.
