Require npm registry signature verification wherever workflow npm audit checks run.
- add npm audit signatures to CI Security Scan and maintenance security audit jobs
- teach the workflow security validator to reject npm audit without signature verification
- keep the repair and Copilot prompt tests portable across Windows path/case and CRLF frontmatter behavior
Validation:
- node tests/run-all.js (2376 passed, 0 failed)
- CI current-head matrix green on #1846
- run non-test workflow installs with npm ci --ignore-scripts where lifecycle scripts are not needed\n- reject plain npm ci in workflows with write permissions\n- reject actions/cache in id-token: write workflows to reduce OIDC publish cache-poisoning risk
