Updated SaveSignatureBehavior.cs to improve functionality:
- Added new dependencies: AutoMapper, IRepository, and EF Core.
- Enhanced constructor to initialize new dependencies.
- Updated Handle method to validate signatures and handle errors.
- Introduced repository operations for querying and updating elements.
- Improved error handling with BadRequestException.
- Cleaned up redundant code and resolved namespace conflicts.
Updated `using` directives to include `DigitalData.Core.Exceptions` for enhanced exception handling. Updated the `[Obsolete]` attribute message to reflect PSPDFKit library deprecation. Renamed `cancellationToken` to `cancel` for consistency.
Added validation to ensure `PsPdfKitAnnotation` is only supported for the `LegacyWeb` receiver type. Introduced stricter checks for missing or invalid annotation data, throwing `BadRequestException` when necessary. Updated `await next` calls to use the renamed parameter.
These changes improve code clarity, enforce stricter validation, and enhance error handling.
Introduced the `SaveSignatureBehavior` class as a pipeline behavior for handling `SigningCommand` requests. Added necessary `using` directives to include required namespaces. Resolved merge conflicts in `using` directives between `net8.0` and `net9.0` project versions. Implemented the `Handle` method to delegate request processing.
