.github/workflows: Migrate workflows to Blacksmith runners

[blacksmith-sh]

This PR has been automatically generated by a team member in your GitHub organization using Blacksmith's Migration Wizard. 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.

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[greptile-apps]

Greptile Summary

The PR migrates the alpha and phone release jobs from GitHub-hosted Ubuntu runners to Blacksmith Ubuntu 24.04 runners.

• Updates the alpha release job to use blacksmith-4vcpu-ubuntu-2404.
• Updates the phone release job to use blacksmith-4vcpu-ubuntu-2404.

Confidence Score: 5/5

The PR appears safe to merge, with no concrete changed-code failure identified.

The changes only replace the runner labels for two release jobs, and the reviewed repository context establishes no incompatible workflow requirement or broken contract.

Important Files Changed

Filename	Overview
.github/workflows/alpha-release.yml	Migrates the alpha build-and-release job to the Blacksmith Ubuntu 24.04 runner; no actionable defect was established.
.github/workflows/phone-release.yml	Migrates the phone release build job to the Blacksmith Ubuntu 24.04 runner; no actionable defect was established.

_{Reviews (1): Last reviewed commit: "Migrate workflows to Blacksmith" | Re-trigger Greptile}