Fail the build if Tier 1 docs leak internal IDs or drift back to known stale pre-v0.2 surface markers. The checks are deterministic and scoped to release-blocking docs only.
Usage
mix mailglass.docs.check
mix mailglass.docs.check --path "guides/**/*.md"Exits 0 if clean. Raises with Delivery blocked: ... brand-voice
message if any internal ID is found.