A hand-placed cut is kept only if it genuinely changes the angle: the plan now
merges surviving cuts with the placed ones, walks the merged list tracking the
EFFECTIVE camera, and drops in-range user cuts whose camera equals it. Real
case: 4.50->cam2 became a no-op once auto-cut placed cam2 at 1.4161 - it
rendered as nothing but read as an edit in the saved file. Removed in the same
group() so it stays one undo; popover and toast report kept vs dropped; cuts
outside the placed range are still never touched.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>