CI/CD & Testing Improvements

[drew]

Roadmap ticket to capture improvements to CI/CD.

Efforts include

• Improve build provenance and dependency supply chain
• Test coverage across drivers and platforms
• Test coverage across GPUs
• Improvements to DX and build infrastructure. Tests and devenvs are reproducible, can be run locally, in an OpenShell sandbox, and in CI. Should be agent friendly.
• Simplify CI/CD pipeline. Less bespoke shell scripts. Artifacts only get built once per platform.
• Speed up tests. Unit and e2e should run quickly on branch checks. Look at selectively running tests based on changes to a branch.