Live camera viewfinder with tap-to-segment interaction

[Monster0506]

Closes #256

Summary

• Implemented live camera streaming helper (wwwroot/js/camera-scanner.js) using navigator.mediaDevices.getUserMedia with back-facing camera selection (facingMode: 'environment'), device switching, and error handling.
• Implemented LiveCameraScanner.razor component with real-time tap-to-segment interaction, freezing frame buffer, and sending tap coordinates to local MobileSAM engine.
• Implemented responsive SVG animated glowing contour overlay snapping around the segmented object.
• Added multi-point refinement support (+ Include / - Exclude points) with visual prompt markers.
• Added action controls: 'Accept item', 'Retap / Cancel', and 'Switch camera'.
• Added mobile layout protections against pull-to-refresh and accidental zoom gestures (touch-action: none, overscroll-behavior: none).
• Fixed ONNX image encoder input tensor shape and rank ([H, W, 3] rank 3 HWC raw float RGB values expected by MobileSAM model).
• Integrated live camera scanner directly into PhysicalAssets.razor review pipeline.
• Added comprehensive unit tests in tests/js/camera-scanner.test.mjs and tests/MoneyMirror.Tests/PhysicalAssets/LiveCameraScannerTests.cs.