chore: checkpoint v22 Gate 0 maintenance

[jerdaw]

Summary

• Finish the v22 Gate 0 C1/D4 evidence guards, including dated D4 artifact-inventory requirements and outreach source-artifact validation.
• Checkpoint the already-started autonomous hardening slice: offline privacy/recovery, pilot event retry/idempotency contracts, OpenAPI coverage, readiness input validation, and privacy-key guards.
• Archive the completed v22 autonomous maintenance record, refresh the checkpoint inventory, and align the roadmap so the remaining path is limited to external C1 legal/API evidence and D4 partner-ops execution evidence.
• Keep authorship guidance human-only across agent docs; CLAUDE.md and GEMINI.md remain relative symlinks to AGENTS.md.

Validation

Latest docs-only maintenance commit uses [skip ci] to conserve GitHub Actions free-tier minutes. Local validation on the latest head:

• npm test from pre-push hook: 198 files passed; 1599 tests passed; 24 skipped.
• Targeted maintenance tests: node node_modules/vitest/vitest.mjs run tests/unit/documentation-hygiene.test.ts tests/scripts/check-v22-evidence-intake.test.ts tests/scripts/check-v22-gate0-exit.test.ts.
• Static/sanity checks: targeted Prettier, tsc --noEmit, node --import tsx scripts/check-references.ts, git diff --check, and bash scripts/check-root-hygiene.sh.
• Expected Gate 0 result remains GATE0_EXIT_NONZERO with blockers G0-3 and G0-8.

Earlier CI on this branch passed validate, actionlint, analyze, static-analysis, unit tests, DB integration, build, and Docker smoke before the docs-only [skip ci] maintenance commit.