[Chore] Temporarily validate mutation gate fixes against PR #1494

[zoomote]

​Created by Roomote. Follow up by mentioning @roomote, in the web UI, or in Discord.

Temporary production validation only. Do not merge. This draft will be closed and its branch deleted after the mutation workflow completes.

What changed

This temporary branch starts at the unchanged head of PR #1494 (9b2a1b112fe2e598da1e3c29cbcb84f7fbf3eeb2) and applies the two reviewed commits from PR #1499.

Why this change was made

The draft exists only to reproduce PR #1494's known mutation-gate path in GitHub Actions while validating PR #1499's merge-ref checkout and package-local Vitest resolution.

Impact

No code from this pull request should be merged. PR #1494 and its source branch are not modified.

[github-actions]

Review process

This PR was opened by an automated account. A human maintainer must verify the change intent, provenance, and validation before merging.

1. Required CI checks pass.
2. The workflow starts CodeRabbit automatically.
3. For eligible human-authored PRs, CodeRabbit reviews and approves the latest commit.
4. A human maintainer reviews and approves after CodeRabbit.

Current step: Wait for the required CI checks to finish.

[codecov]

Codecov Report

❌ Patch coverage is 85.00000% with 6 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/core/webview/ClineProvider.ts	81.81%	2 Missing and 4 partials ⚠️

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