nx_fwdconst_scan_gate.nx

nx_fwdconst_scan_gate.nx -- GATE for the forward-const detector (4 teeth incl embedded negatives). PREREQ: stage _offc/nx_fwdconst_scan.elf first. Run from nxc2 root. ONE scanner fork total. T1 exactly one FWDCONST row on the 5-fixture dir | T2 the row names bad.nx + const=BADC | T3 summary files=5 flagged=1 | T4 negatives: good(decl-above), cmt(comment-line mention), str(quoted mention), sub(word-boundary FOOX vs FOO) all UNFLAGGED. Mutation proof (manual): drop the word-boundary check in fw_first_use -> sub.nx flags -> T1+T3 RED. license_tier: ORIGINAL No hw writes (Rule 26).