nx_mm_probe_marker.nx

RETIRED PROBE ARTIFACT -- kept as a one-line marker, not deleted, so the finding stays traceable. This file existed only to discriminate whether /api/unpack OVERWRITES or only ADDS. It was packed alongside an ALREADY-PRESENT changed file: unpack reported files=1 failed=0, this new file landed, and the changed one did NOT -- proving the sync path is ADD-ONLY and reports the skip as success. Full finding + fix direction: nx_debt id 1785523434 (sev 9).