chore: pin GitHub Actions to full-length commit SHAs

[joshuarli]

Summary

• Pin all GitHub Actions references in .github/ workflow files to full-length commit SHAs

Generated by devenv pin_gha.

🤖 Generated with Claude Code

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

📋 Changelog Preview

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New Features ✨

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

Internal Changes 🔧

• 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

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