- Refactor index.ts to skip start() when NODE_ENV=test
- Add test setup with mocks for db, keys, browser, verification, email, usage
- Add vitest.config.ts with setup file
- Rewrite tests to work with mocks (42 tests, all passing)
- Add new tests: signup 410, recovery validation, CORS headers, error format, API root
- Add test step to CI pipeline before Docker build
