Init --ci and reusable workflow for health gating (#203 follow-up)

[mojoatomic]

Goal
Make CI gating trivial for consumers: scaffold workflows/scripts and provide a reusable GitHub Action/workflow.

Tasks

• CLI: init --ci flag
  • Generate ci-ratchet.yml (ratchet-and-tests job)
  • Ensure package.json scripts: lint:json, analyze:current, ratchet, ratchet:context
  • Optional hints for branch protection required checks
• Reusable option
  • Publish a composite action or reusable workflow that runs lint-json → analyze → ratchet → context
  • Document required job name(s) and how to set branch protection
• Docs
  • One-pager: “Enable health gating in CI” (copy-paste + minimal tweaks)

Acceptance Criteria

• init --ci generates working CI and scripts without breaking existing setups
• Reusable Action/workflow published and documented
• Guide includes required check names and when to flip health.enabled

References

• Health Gating Enforcement for Context-Aware Ratchet #203 Health gating enforcement
• feat: permissive-start + progressive ratchet scaffolding #211 permissive-start + CI-safe scripts
• ci: enforce health gate (remove continue-on-error; run ratchet:context normally) #213 CI enforcement

[mojoatomic]

#216 implemented via #218: init --ci scaffolds CI workflow; reusable workflow added. Moving to #215 to write docs in one pass including these new options.