test(optimize): clean up pnpm v8 and v9 fixture artifacts after tests

[Simon (simonhj)]

The pnpm v8/v9 optimize fixture tests run pnpm install inside the fixture directories during beforeEach to provision the specific pnpm binary version. The existing afterEach hooks only reset tracked files (git checkout HEAD -- .) but left untracked node_modules/ and .cache/ directories behind, polluting the working tree for both pnpm v8 and pnpm v9 fixtures.

This caused two problems for both fixtures:

1. Running git add -A (or relying on pre-commit hooks that do) would accidentally stage thousands of untracked fixture artifacts.
2. The pnpm9 fixture install was silently failing (swallowed by try/catch + stdio: 'ignore'), so pnpm9 tests fell back to the system pnpm rather than testing against pnpm v9.

Changes

• Import trash and remove node_modules/ + .cache/ in both beforeEach (to clean up after prior aborted runs) and afterEach (to keep the fixture clean going forward) for both pnpm8 and pnpm9 fixtures.
• Use Promise.all for parallel cleanup to avoid no-await-in-loop lint warnings.

Verification

• All 4 pnpm-version tests continue to pass.
• Fixture directories are now clean after each test run (only package.json and pnpm-lock.yaml remain).

---

Note

Low Risk
Low risk: test-only changes that add cleanup of node_modules/.cache in fixtures; main impact is slightly longer test setup and potential environment-specific filesystem deletion behavior.

Overview
Keeps the pnpm8/pnpm9 optimize fixture tests from leaving behind untracked install artifacts by deleting node_modules/ and .cache/ in both beforeEach (cleanup from prior runs) and afterEach (post-test cleanup).

The tests now use trash and run cleanup in parallel via Promise.all, while still resetting tracked files via git checkout.

^{Reviewed by Cursor Bugbot for commit 6f7d89d. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is ON. A cloud agent has been kicked off to fix the reported issue.}

Comment @cursor review or bugbot run to trigger another review on this PR

^{Reviewed by Cursor Bugbot for commit 6f7d89d. Configure here.}

[Martin Torp (mtorp)]

Good catch ✅