- multi_agent_restart_is_one_dag_with_concurrent_per_agent_subgraphs:
two agents restart in one DAG; both SetWanted heads are roots, each
acquiring its own agent's lease concurrently. Existing single-agent
shape/lease tests updated for the templates::restart(&[..], graceful)
signature.
- coordinator.md + templates.rs module doc: restart takes an agent list;
a hive-wide restart is one DAG with N per-agent subgraphs.