feat(agents): Update one stale example per workflow run
The examples agent treated "update our examples" as a single run over
every example. Split that into dispatch work and update work:
- Add `find_stale_examples`, which reads each `examples/<name>` commit
date from GitHub and marks an example stale after a week without a
commit. Examples touched by an open pull request are reported as
skipped so the agent never opens a duplicate.
- Enable the experimental `Workflow` tool so a broad request fans out
one child run per queued example, each opening a single pull request
on `agents/examples/<example>`.
- Move the GitHub App auth and request plumbing out of
`create_pull_request` into `agent/lib/github.ts`, and add the pull
request, pull request file, and commit queries the new tool needs.
- Rewrite the instructions, the maintenance skill, and the weekly audit
prompt around the per-example contract.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Co-Authored-By: Anthony Shew <35677084+anthonyshew@users.noreply.github.com>