docs: rebase onto current main -- add the page to the nav and repoint the operator-runbook link

- mkdocs.yml: list 'Working with the agent' in the nav (a page not in the
  nav is hard to find).
- working-with-the-agent.md: the operator token runbook moved out of the
  published site into the git-only co-op/ops-docs, so the relative link
  (operator-token-runbook.md) would 404; point it at the runbook's new home
  in ops-docs, as infrastructure.md already does. Wording unchanged.

mkdocs.yml

@@ -74,6 +74,7 @@ nav:
   - Energy & carbon: energy.md
   - Infrastructure: infrastructure.md
   - Background: background.md
+  - Working with the agent: working-with-the-agent.md
   - Governance:
       - Charter: charter.md
       - Code of conduct: code-of-conduct.md

working-with-the-agent.md

@@ -70,8 +70,9 @@ access today, so say what you saw in #general and the operator acts. Stopping
 is not restarting: the backup and the git mirror restore state, not uptime,
 and someone has to start the agent again. The steps, and the steps for
 rotating everything an agent holds, are in the agent's runbook; the credential
-inventory in the [operator token runbook](operator-token-runbook.md) says what
-that is.
+inventory in the [operator token
+runbook](https://git.inference.coop/co-op/ops-docs/src/branch/main/operator-token-runbook.md)
+says what that is.
 
 Changes to this page are policy: propose them in the
 [forum](https://forum.inference.coop).