docs: add list_containers to agent lifecycle tools in turn-loop.md

docs/turn-loop.md

@@ -397,6 +397,9 @@ it as a stdio child via `--mcp-config`. The hyperhive socket name is
   No approval required. Topology-enforced: `name` must be a direct child
   per `topology.json`. Server rejects all other agent names. Requires
   `lifecycle` tool group.
+- `list_containers()` — list all descendant containers with running
+  status. Topology-enforced (descendants only). Requires `lifecycle`
+  tool group.
 - `request_init_config(name, description?)` — step 1 of spawning a new
   direct child agent. Queues an `InitConfig` approval; on operator
   approve, hive-c0re seeds the proposed config repo with a default