Port the safe, narrow pieces from contributor PR #1694 without taking the broad 11-skill rewrite.
- add drift-prone warnings to external research/media/API skills
- make search-first verify tool availability and use current agent naming
- remove unsafe in-memory rate limiter example from backend patterns
- tighten the CSP example in security-review
Validation: node scripts/ci/validate-skills.js --strict; npx markdownlint targeted skill files; node tests/ci/validators.test.js && node tests/ci/catalog.test.js; npm run lint; node tests/run-all.js
Add origin field to all skill files to track their source repository.
This enables users to identify where distributed skills originated from.
Fixesaffaan-m/everything-claude-code#246
