Bind a CameraX ImageAnalysis use case that runs EdgeDetector on downscaled
YUV frames (throttled ~6/s) and draw the detected document quad as a live
green overlay on the preview, mapped through the FILL_CENTER crop. Preview
switched to TextureView (COMPATIBLE) mode so the Compose overlay renders on
top. Bump versionCode 4 / versionName 0.2.0.
Fixes#4
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
