GitHub is hiding old checks, making log retrieval difficult

I went to go look at Buildomat logs for https://github.com/oxidecomputer/transceiver-control/commit/4aac6125a8e6cefbb71d9f8a3d1fe6704207d476 and discovered that GitHub is no longer showing the checks interface for commits beyond a certain time frame. (The cutoff is somewhere between 409 and 416 days ago.)

They are also not present in the API:

$ curl https://api.github.com/repos/oxidecomputer/transceiver-control/commits/4aac6125a8e6cefbb71d9f8a3d1fe6704207d476/check-runs
{
  "total_count": 0,
  "check_runs": [

  ]
}

By design Buildomat requires going through the GitHub checks interface to view logs so that you, in theory, are authorized to view the repository in order to get the log output and the job artefacts.

Start by reproducing the missing checks and empty check-runs response for commit 4aac6125a8e6cefbb71d9f8a3d1fe6704207d476, then review Buildomat's GitHub checks and log-access flow. The issue names no repository file or test, and it does not define a change or acceptance criteria for cases where GitHub no longer exposes the checks.