POC: support TypeScript plugins in find plugin manager via esbuild

[Copilot]

Summary

Implement a proof-of-concept in .github/actions/find/src/pluginManager.ts to load custom and built-in plugins from index.ts first (compiled at runtime with esbuild) and fall back to index.js.

Changes

• Added runtime TypeScript plugin support in pluginManager:
  • resolve plugin entry as index.ts first, then index.js
  • compile index.ts with esbuild (bundle, esm, platform: node, target: node24)
  • import compiled output via data: URL
  • keep existing plugin skip/registration behavior
• Updated dynamic import helper to support importing data: and file: URLs directly.
• Added tests in .github/actions/find/tests/pluginManager.test.ts for:
  • preferring index.ts when both TS/JS entrypoints exist
  • falling back to index.js when TS entrypoint is absent
• Added esbuild dependency in .github/actions/find/package.json and updated lockfile.

Validation

• npm run lint (repo root)
• npx vitest run .github/actions/find/tests/pluginManager.test.ts .github/actions/find/tests/findForUrl.test.ts
• npm --prefix .github/actions/find run build
• parallel_validation (Code Review + CodeQL): no remaining comments, no CodeQL alerts

Notes

• Baseline repo-wide npm test still includes an existing environment-dependent failure when CACHE_PATH is not set (tests/site-with-errors.test.ts), unrelated to this change.