test: Webpack integration tests

[timfish]

This PR follows #899 and the previous PRs by adding webpack tests

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

---

New Features ✨

• Use crypto.randomUUID rather than uuid by timfish in #892

Internal Changes 🔧

• Webpack integration tests by timfish in #904

• Isolate integration test package installs by timfish in #902
• Pin GitHub Actions to full-length commit SHAs by joshuarli in #900
• Rollup integration tests by timfish in #897
• New integration tests by timfish in #896
• Remove lerna by timfish in #895
• Migrate to Vitest by timfish in #894

---

_{🤖 This preview updates automatically when you update the PR.}

[cursor]

Cursor Bugbot has reviewed your changes and found 2 potential issues.

^{Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

[chargome]

q: Are we testing on pinned versions intentionally?

[timfish]

Yes mainly because we're snapshotting the output. Don't really want all the tests failing when any bundler changes their output. Probably less of an issue with webpack as it doesn't change mutch.