chore(release): enforce documentation surface parity

[kevintseng]

Summary

• make CODEMAP version, package bins, hook commands, and local messaging anchors fail the release gate when stale
• bind the canonical MCP tool contract to the three READMEs, AGENTS.md, the MeMesh skill, API reference, and architecture overview
• correct v4.8.1 documentation drift found by an independent audit: all 11 skill tools, 11 MCP handlers, 8 hooks, required merge_strategy, and experimental Gemini ACP status
• keep the release path small: one focused CODEMAP checker plus the existing MCP documentation checker

Verification

• npm run test:surface-parity
• npm run verify:release
• exact-head CI matrix on Linux, macOS, and Windows
• packaged artifact and upgrade smoke tests
• focused negative paths for stale version, missing bin/hook/messaging anchors, missing tool rows/API sections, architecture inventory drift, and canonical MCP contract drift

This is a post-v4.8.1 follow-up. It does not rewrite the published v4.8.1 tag or npm tarball.