fix(I-26): spec_conformance.sh — a §12 expiry is the Expires marker, never the first date in the cell; rows past expiry are RED (the §4 andon); derived_expiries.json regenerated (row 1 → 2026-09-19) (PMAT-974, #2889)

fix(I-26): spec_conformance.sh — a §12 expiry is the Expires marker, never the first date in the cell; rows past expiry are RED (the §4 andon); derived_expiries.json regenerated (row 1 → 2026-09-19) (PMAT-974, #2889) #648