[codex] Improve RepoPulse audit engine

[Milborne]

Summary

• Refactors RepoPulse into a richer offline audit engine with path type validation, content validators, README EN/ES section detection, exclusions, custom weights, and clearer scoring.
• Adds text, Markdown, and JSON reporting plus GitHub Step Summary support and structured JSON outputs.
• Adds CI, Dependabot, ESLint, Prettier, expanded tests, updated docs, CHANGELOG, and release guidance.

Validation

• npm ci
• npm run check
• npm audit --audit-level=moderate
• git diff --exit-code dist/index.js
• node dist/index.js

Notes

GitHub Marketplace can reject action repositories that contain workflow files. This PR keeps CI for maintainability and documents the release workaround if Marketplace validation blocks a future release.