P0 Task 5. RetailTrace parses the [fcl] golden format (seed/pos/picked,
RetailCellPick); 4 TDD tests green. find-cell-list-capture.cdb targets
CPhysicsObj::change_cell (commit-on-diff) to capture retail's accepted
membership sequence at the doorway; README is the operator runbook
(dt offset verification + decode_retail_hex float decode). The live run
is P0's one user-gated step (Task 6 mines existing traces first).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
