Description of Changes

Stop building ghaf devshell in github-hosted runners and move the pre-commit checks and ghaf shell builds to build.yml.

Before this change eval.yml ran nix develop --command .github/eval.sh ... which would to build the full ghaf devshell in a github-hosted runner.
Similarly, check.yml built checks.x86_64-linux.pre-commit in a github runner.
Building such targets in github-hosted runners is slow and might fail, due to the very limited resource in the github-hosted runners (and due to patches we might carry in github:tiiuae/nixpkgs that could trigger big re-builds).

This PR changes the eval.yml so that it does not build the full ghaf devshell, but runs the eval.sh in a custom shell including only the binaries the script requires (jq, nix-eval-jobs). In addition, this change moves the pre-commit checks and devshell build to the build.yml, which runs the builds on our remote builders that have sufficient resources. Additional benefit from these changes is: we now also push the ghaf devshell to ghaf-dev cachix cache.

Type of Change

• New Feature
• Bug Fix
• Improvement / Refactor

Related Issues / Tickets

Checklist

• Clear summary in PR description
• Detailed and meaningful commit message(s)
• Commits are logically organized and squashed if appropriate
• Contribution guidelines followed
• Ghaf documentation updated with the commit - https://tiiuae.github.io/ghaf/
• Author has run make-checks and it passes
• All automatic GitHub Action checks pass - see actions
• Author has added reviewers and removed PR draft status

Testing Instructions

Applicable Targets

• Orin AGX aarch64
• Orin NX aarch64
• Lenovo X1 x86_64
• Dell Latitude x86_64
• System 76 x86_64

Installation Method

• Requires full re-installation
• Can be updated with nixos-rebuild ... switch
• Other:

Test Steps To Verify:

1. ...