Blazor ID Auto-Crop Function

I need a self-contained C# routine for my existing Blazor Server app that takes an uploaded photo—whether shot on a phone or chosen from disk—detects the driver’s licence, passport page or other ID card inside it, crops away the background, and returns the document perfectly oriented. The routine has to run locally in .NET, rely only on open-source libraries that carry no licensing fees, and ship with complete source code so I can compile and maintain it myself.

The service must accept JPEG, PNG and BMP files. If the algorithm cannot confidently find the document edges and complete the crop, it must signal failure so I can immediately reject the upload; no fallback to manual editing.

You are free to build with OpenCV (e.g., OpenCvSharp), ImageMagick, ImageSharp or a custom algorithm—anything that is genuinely free of charge—but no commercial SDKs, paid APIs or per-use cloud calls may appear anywhere in the stack.

Deliverables:
• Well-commented C# class or service that exposes a single call returning the cropped, deskewed image or a failure flag
• Any helper methods or models required, packaged so I can drop the code into my solution and wire it to the existing upload endpoint
• A brief README explaining library versions, configuration hints and basic usage in a Blazor page
• A small test project or snippet that demonstrates the detection passing and failing on sample images

When the code meets these points and builds cleanly under .NET 7 in Visual Studio, the job is done.