Add restricted SSH admin shell

AGENTS.md

@@ -198,7 +198,10 @@ Roadmap items should be actionable and checkable:
   CLI streams through the local daemon, the daemon uses `/geth/ssh-proxy/1` over
   Iroh, the remote daemon requires `ssh_proxy.connect` on
   `resource:ssh-proxy:local`, and only then connects to `127.0.0.1:22`. SSH is
-  still not a geth transport backend.
+  still not a geth transport backend. `geth ssh admin-shell <node-id>
+  <help|status|node-id>` is a restricted geth admin workflow over the protected
+  Iroh control path, requires `ssh_proxy.admin_shell`, and never executes host
+  shell commands.
 - Resource secret epoch metadata can be created, rotated, and listed locally.
   Bearer access metadata can be created/listed/revoked as resource-scoped auth
   ops and must not allow trust graph mutation capabilities. Bearer