Dragging a crop handle past the image edge used to hand the raw rectangle to
CropGeometry::constrained, which slid the whole frame toward the centre and
moved the anchored corner. drag_crop owns the drag instead: the opposite
edges stay put, a locked ratio holds on all eight handles (edges grow about
their midline, sliding along a blocked side), the frame stops at the image
edge and slides along it, and it keeps a minimum size. Hostile numbers return
the start crop. Covered by Given/When/Then scenarios and property tests.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Nathaniel LedfordandClaude Sonnet 5.5
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