ci-templates v2026.09.26 — exact-zero release ratchet (ADR-066)

.release-ratchet-zero now lives in cross-cutting-lint.yml on the
hash-pinned runner; --require-zero rejects TODO(HUMBLE)-marked sites and
nonzero stored counters. Also carries bf037bb, 52e3e80, 3af54ff,
6b9590c, 2236efb since v2026.09.07.