Switch to Blacksmith runners for CI

[skyfallwastaken]

In theory at least, these should be way faster!

[greptile-apps]

Greptile Summary

This PR migrates all CI jobs from GitHub's standard ubuntu-latest runners to Blacksmith's blacksmith-4vcpu-ubuntu-2404 runners. The change affects 6 active jobs (scan_ruby, scan_js, lint, frontend, zeitwerk, test) plus one commented-out test job.

Key changes:

• All runs-on: ubuntu-latest declarations replaced with runs-on: blacksmith-4vcpu-ubuntu-2404
• No changes to job logic, dependencies, or workflow structure
• Consistent application across all jobs in the file

Impact:

• Expected performance improvement through 4-vCPU dedicated runners
• Uses Ubuntu 24.04 as base image (vs Ubuntu 22.04 in ubuntu-latest)
• No compatibility concerns - Blacksmith runners are GitHub Actions-compatible

Confidence Score: 5/5

• This PR is safe to merge with minimal risk - it's a straightforward infrastructure change
• The change is purely infrastructure-related, switching runner types without modifying any job logic, dependencies, or workflow structure. Blacksmith runners are GitHub Actions-compatible and the change is applied consistently across all jobs. No code, tests, or functionality are affected.
• No files require special attention

Important Files Changed

Filename	Overview
.github/workflows/ci.yml	All CI job runners switched from ubuntu-latest to blacksmith-4vcpu-ubuntu-2404 for faster execution

_{Last reviewed commit: 8482240}

[Copilot]

Pull request overview

Updates the CI workflow to use Blacksmith-provided Ubuntu 24.04 runners instead of ubuntu-latest, aiming to speed up job execution across the pipeline.

Changes:

• Switch runs-on for all active CI jobs from ubuntu-latest to blacksmith-4vcpu-ubuntu-2404.
• Update the commented-out test job runner label to match the new runner.

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[Copilot]

The runner label is repeated across multiple jobs. Consider defining it once (e.g., via a YAML anchor/alias or a top-level env + expression in runs-on) to avoid missed updates if the runner name changes again.