chore: implement repo improvements plan (npm scripts, docs, catalog CI, i18n, validator)

- Add npm scripts: validate, validate:strict, index, readme, chain, catalog, build
- Align docs to V4 and 560 skills (GETTING_STARTED, FAQ, BUNDLES, MAINTENANCE, vietnamese)
- build-catalog: output to data/ for catalog, bundles, aliases; add to CI and drift check
- Add yaml dep, Node setup and catalog step in CI; extend auto-commit and drift msg
- Translate CI and MAINTENANCE to English; update CI_DRIFT_FIX and maintenance routine
- QUALITY_BAR/CONTRIBUTING: canonical validator npm run validate; legacy note in validate-skills.js

scripts/validate-skills.js

@@ -1,3 +1,7 @@
+/**
+ * Legacy / alternative validator. For CI and PR checks, use scripts/validate_skills.py.
+ * Run: npm run validate (or npm run validate:strict)
+ */
 const fs = require('fs');
 const path = require('path');
 const { listSkillIds, parseFrontmatter } = require('../lib/skill-utils');