The 3D viewer was only seeing points inside the ROI rectangle used for
the plane fit. Now /fit also fetches nuwa.pointcloud (step=4, full frame),
flips to CV frame, and returns it as points_camera (downsampled to
max_preview_points). The user sees the entire scene with red = excluded
by the below-plane filter, cyan = kept.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
POST /fit returns a candidate WorkPlane + a downsampled CV-frame cloud
preview, without writing to disk. POST /save persists the plane. GET
returns the current saved plane (or null). DELETE clears it.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
