HARD i18n rules digest for the oss-docs harness specialists working on moai-adk-go README 4-locale set and the docs-site (adk.mo.ai.kr). Covers the canonical-locale chains, the 4-locale same-PR obligation, Mermaid TD-only, the no-emoji + icon-shortcode rule, emphasis-marker spacing, the URL blacklist, version SSOT, vercel.json redirect pattern, and the immutable Vercel binding. Loaded FIRST by every oss-docs specialist before any edit.