Add a Vitest case that mocks `node:child_process.spawn` so the child
emits `error` (ENOENT) after the constructor attaches listeners.
`getQuotaWindows()` must resolve with `ok: false` instead of leaving an
unhandled `error` event on the process.
Register `packages/adapters/codex-local` in the root Vitest workspace.
Document in DEVELOPING.md that a missing `codex` binary should not take
down the API server during quota polling.
