docs: remove common-cache references from documentation and tooling

Remove all remaining references to common-cache from project documentation,
test workflows, and build tooling after action deletion.

Updated:
- CLAUDE.md: Remove from action catalog (28 → 27 actions)
- README.md: Regenerate catalog without common-cache
- SECURITY.md: Update caching optimization notes
- Test workflows: Remove common-cache test references
- spec_helper.sh: Remove common-cache test helpers
- generate_listing.cjs: Remove from category/language mappings
- update-validators.py: Remove custom validator entry

_tests/integration/workflows/lint-fix-chain-test.yml

@@ -7,7 +7,6 @@ on:
       - 'eslint-lint/**'
       - 'prettier-lint/**'
       - 'node-setup/**'
-      - 'common-cache/**'
       - '_tests/integration/workflows/lint-fix-chain-test.yml'
 
 jobs: