chore: correctly apply web-test-runner-coverage patch

[rubencarvalho]

Description

Corrected the location and application of the @web/test-runner-coverage-v8 patch to properly handle code coverage for files outside the test runner's root directory.

Motivation and context

The patch file was previously created in the wrong location (patches/) and with incorrect formatting, so it was never actually being applied by Yarn. This meant coverage generation was still failing for cross-workspace imports.

This PR corrects the patch location and application method to follow Yarn Berry's patch system properly (expects patches in .yarn/patches/, not patches/).

This prevented coverage reports from being generated correctly and caused test failures in CI when coverage was enabled.

Related issue(s)

• fixes [Issue Number]

Screenshots (if appropriate)

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Author's checklist

• I have read the CONTRIBUTING and PULL_REQUESTS documents.
• I have reviewed at the Accessibility Practices for this feature, see: Aria Practices
• I have added automated tests to cover my changes.
• I have included a well-written changeset if my change needs to be published.
• I have included updated documentation if my change required it.

---

Reviewer's checklist

• Includes a Github Issue with appropriate flag or Jira ticket number without a link
• Includes thoughtfully written changeset if changes suggested include patch, minor, or major features
• Automated tests cover all use cases and follow best practices for writing
• Validated on all supported browsers
• All VRTs are approved before the author can update Golden Hash

Manual review test cases

• Check if the testing coverage CI actions in this PR runs correctly, without errors like this:

Error while generating code coverage for https://*****host:8000/__wds-outside-root__/1/2nd-gen/packages/core/dist/shared/base/index.js.
Error: ENOENT: no such file or directory, open '/root/project/1st-gen/__wds-outside-root__/1/2nd-gen/packages/core/dist/shared/base/index.js'
    at async open (node:internal/fs/promises:633:25)
    at async readFile (node:internal/fs/promises:1237:14)
    at async v8ToIstanbul (/root/project/node_modules/@web/test-runner-coverage-v8/dist/index.js:79:46)
    at async PlaywrightLauncherPage.stopSession (/root/project/node_modules/@web/test-runner-playwright/dist/PlaywrightLauncherPage.js:30:15)
    at async PlaywrightLauncher.stopSession (/root/project/node_modules/@web/test-runner-playwright/dist/PlaywrightLauncher.js:83:24) {
  errno: -2,
  code: 'ENOENT',
  syscall: 'open',
  path: '/root/project/1st-gen/__wds-outside-root__/1/2nd-gen/packages/core/dist/shared/base/index.js'
}

[changeset-bot]

⚠️ No Changeset found

Latest commit: ad03c35

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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[github-actions]

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