Vitest runs test files in parallel workers. Each worker imports server/db.js,
which triggered module-level init(DEFAULT_PATH) unconditionally. Two workers
racing to open the same SQLite file caused "database is locked", followed
by process.exit(1) killing the worker — surfacing as:
Error: process.exit unexpectedly called with "1"
Fix: guard the boot init block behind NODE_ENV !== 'test'. Vitest sets
NODE_ENV=test automatically. Each worker's beforeEach(() => _resetForTest())
initialises its own :memory: database, so no file coordination is needed.
process.exit(1) is also guarded by the same condition — it must never
fire inside a test runner process.
TDD: two regression tests added to tests/db.test.js documenting the
expected boot behaviour and proving the module loads cleanly in parallel.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>