.github/workflows: Migrate workflows to Blacksmith runners

[blacksmith-staging]

To whomever may be reviewing this PR,

Blacksmith is the fastest way to run your GitHub Actions.

What does this PR change?

This PR has been automatically generated by a team member in your GitHub organization using Blacksmith's Migration Wizard, or MigWiz for short. This PR changes the following:

1. Your selected workflows will now run on Blacksmith's 2x faster hardware (e.g., runs-on: blacksmith-4vcpu-ubuntu-2204). Learn more about the different instances available to choose from.
2. Your jobs running on Blacksmith will now have all official GitHub and popular third-party cache actions automatically interact with our 4x faster, colocated cache. Learn more about Blacksmith's actions cache.
3. Your GitHub Actions will now actually be observable. Learn more about Blacksmith's logging and other observability features.
4. Your Docker builds will now automatically share their Docker layer cache, resulting in up to 40x faster builds. Learn more about Blacksmith's Docker layer caching.

FAQ

• Is this free? The first 3,000 minutes per month are free.
• Who uses Blacksmith? Clerk, Ashby, VEED, and 600+ others.
• What's the catch? There is none. Merge this thing already.

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• Let Codesmith autofix CI failures and bot reviews

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^{Need help on this PR? Tag @codesmith with what you need.}

• Let Codesmith autofix CI failures and bot reviews (Staging)

[cursor]

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

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^{Reviewed by Cursor Bugbot for commit 3ad3149. Configure here.}