* feat: set up Vitest frontend testing infrastructure with CI workflow
Migrate existing 4 frontend test files from Node.js native test runner
(node:test + node:assert/strict) to Vitest, reorganize test directory
structure under tests/unit/ mirroring src/ layout, and add a dedicated
CI workflow for frontend unit tests.
- Add vitest as devDependency, remove tsx
- Create vitest.config.ts with @/ path alias
- Migrate tests to Vitest API (test/expect/vi)
- Rename .mjs test files to .ts
- Move tests from src/ to tests/unit/ (mirrors src/ layout)
- Add frontend/Makefile `test` target
- Add .github/workflows/frontend-unit-tests.yml (parallel to backend)
- Update CONTRIBUTING.md, README.md, AGENTS.md, CLAUDE.md
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
* style: fix the lint error
* style: fix the lint error
---------
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Willem Jiang <willem.jiang@gmail.com>
