_drop_piece looked up plan.item(item.pid), but item.pid is a Placement id (pl2)
while CutPlan.item() expects a CutItem id (ci2) — every drop raised StopIteration
before validate/revert could run. Use the already-found placement's item_id
(plan.item(p.item_id)) for the stock-compat check and message.
Added tests/test_bom_window.py (offscreen QGraphicsScene): drop-overlap reverts
without crashing, drop-onto-incompatible-stock reverts, and a valid move commits.
128 tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
