Introduced the `DualInputDocumentFilter` class to merge Swagger operations with the same path but different `[Consumes]` attributes (`multipart/form-data` and `application/json`) into a single operation. This ensures both content types are visible in the Swagger UI.
Updated `SwaggerConfiguration.cs` to:
- Resolve conflicting actions by keeping the first variant.
- Register the `DualInputDocumentFilter` to enable content type merging.