Browser Mode: Vite warns Plugin "vitest:mocks:interceptor" defines Vite-specific hooks (configureServer) in a plugin returned from applyToEnvironment on every run

Describe the bug

With test.browser.enabled: true, every vitest run prints once:

Plugin "vitest:mocks:interceptor" defines Vite-specific hooks (configureServer) in a plugin returned from applyToEnvironment. These hooks will be ignored.

Cause: @vitest/browser adds interceptorPlugin({ registerWebSocketEvents: false }) (from @vitest/mocker) to the browser contribution, which vitest:browser:loader.applyToEnvironment returns for the client environment. The mocker's interceptorPlugin always defines configureServer (its body returns early when registerWebSocketEvents === false), and Vite 8's resolveEnvironmentPlugins warns for any config / configEnvironment / configureServer / configResolved hook on a plugin returned from applyToEnvironment. Tests and mocking work; the warning is noise on every run.
Suggested fix: attach configureServer only when registerWebSocketEvents !== false (packages/mocker/src/node/interceptorPlugin.ts), or strip the hook in the browser contribution.

I do not plan to submit a PR. Used Claude Code to generate this report.

Reproduction

Link to the GitHub repository with the Reproduction — npm install && npm test.

Bare config: one chromium instance via @vitest/browser-playwright, one passing test, no plugins.
Actual: The warning above is printed once per run.
Expected: no warning. (The same happens in a 200-file production suite; the minimal repo is the stripped-down version.)

System Info

System:
    OS: Windows 11 10.0.26200
    CPU: (16) x64 Intel(R) Core(TM) Ultra 7 265H
    Memory: 6.38 GB / 31.46 GB
Binaries:
    Node: 24.20.0 - C:\nvm4w\nodejs\node.EXE
    npm: 11.19.1 - C:\nvm4w\nodejs\npm.CMD
Browsers:
    Chrome: 152.0.7977.84
    Edge: Chromium (147.0.3912.72)
npmPackages:
    @vitejs/plugin-react: 6.1.1 => 6.1.1 
    @vitest/browser-playwright: 5.0.0 => 5.0.0 
    @vitest/coverage-v8: 5.0.0 => 5.0.0 
    @vitest/eslint-plugin: 1.6.27 => 1.6.27 
    @vitest/ui: 5.0.0 => 5.0.0 
    playwright: 1.63.0 => 1.63.0 
    vite: 8.3.0 => 8.3.0 
    vitest: 5.0.0 => 5.0.0 
    vitest-browser-react: 2.3.0 => 2.3.0

Used Package Manager

npm

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Start with packages/mocker/src/node/interceptorPlugin.ts and reproduce the warning using the linked browser reproduction with npm install && npm test. Review how configureServer is attached when registerWebSocketEvents is false; done means the browser-mode run completes without the Vite warning while tests and mocking continue to work.