Why
CAPTURE.md Crop keeps slab pixels and makes removed pixels transparent.
encodeInventoryPng only drawImage-cropped the AABB from the raw photo.
Scope
composeInventoryFrame samples the source through approvedMask.bitset.
Non-slab pixels stay alpha 0. Drop the 8% MARGIN; fill 80% of mask
extents in a 3:4 frame. Floor rules unchanged.
Verification
cd frontend && npm test
12 pass, including alpha contract (no sheet green in opaque pixels).
grokbot_ty
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