Bounty: Speedup CI setup to <20s using native install

[nkhatpe]

This PR replaces the Docker-based environment setup with a minimal native pip-based install to dramatically reduce CI setup time.

Summary

• Replaces eval $BUILD in .github/workflows/setup/action.yaml with native install
• Uses GitHub Actions caching for pip
• Only installs essential Python packages:
  • numpy, pycapnp, psutil, tqdm
• Skips Docker pull/build entirely
• Confirmed to work on default GitHub-hosted runners (ubuntu-latest)

Benchmark

• Setup time: 17 seconds
• Well under the <20s requirement for full bounty

Relevant bounty issue:

#30706

Tested in my fork:

• GitHub Actions successful run (~17s)

Thank you for reviewing! I’d love to continue contributing to openpilot and take on more bounties.

[github-actions]

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• Convert your PR to a draft unless it's ready to review
• Read the contributing docs
• Before marking as "ready for review", ensure:
  • the goal is clearly stated in the description
  • all the tests are passing
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[adeebshihadeh]

I assume this is a draft?

[nkhatpe]

Yes, this is still a draft. I’m actively working on optimizing the setup and testing different caching strategies. Will mark it ready for review once it's stable.