@stylexjs/unplugin Vite shared-store timer survives Vitest shutdown without httpServer

Versions

• @stylexjs/unplugin: 0.19.0
• Vite: 6.4.3
• Vitest: 4.1.0
• Node: 24.20.0, macOS arm64

Reproduction

Use the recommended Vite integration in a shared Vite/Vitest config:

import { defineConfig } from 'vitest/config';
import stylex from '@stylexjs/unplugin';
export default defineConfig({ plugins: [stylex.vite({ useCSSLayers: false })] });

Run vitest run against a passing test suite. The tests pass, then Vitest waits ten seconds and reports:

close timed out after 10000ms
Tests closed successfully but something prevents Vite server from exiting

Source evidence

packages/unplugin/src/vite.ts / published lib/vite.js installs a 150ms setInterval in configureServer when the shared store is present. Cleanup is registered only with server.httpServer?.once('close', ...). Vitest's server does not provide the normal HTTP-server lifecycle, leaving this timer alive.

Expected

The plugin should release/unref its timer when Vite's plugin container closes even without an HTTP server, so a test run exits normally.

Local workaround

For process.env.VITEST, use the same package's stylex.rollup({ useCSSLayers: false }) compiler adapter, leaving stylex.vite(...) for browser dev/build. The same suite then exits cleanly without changing tests or timeouts. This is a non-blocking upstream follow-up; no dependency patch is needed locally.