Add the 3 tests the spec-compliance review flagged: 0x0022 ConfirmMove clears
the pending move (no rollback after a confirm); OnDragOver advisory-accepts a
closed bag (cap>0, contents not indexed = AP-61); App-level drop -> RollbackMove
reverts the optimistic move to the original container+slot. Production code was
already correct; these exercise the spec's test plan.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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