v0.5.1

Added (M9)

• audit --format github: workflow-command output for any CI that speaks
  GitHub Actions annotations — ::error/::warning/::notice with
  file/line backlinks from finding evidence, spec-compliant escaping, and a
  summary notice. No Action installation required.
• action/ — the complete composite Action (action.yml + Marketplace
  README), ready for the maintainer to push to the reprollm/action repo.
  Inputs: path, fail-on, level, version, check-lock; outputs:
  critical-count, warning-count; steps include a Step Summary table and an
  artifact upload.
• CI now self-audits ReproLLM with --format github (bootstrapped
  dogfooding in the Checks tab).