fn muxbus_agent_id_from_env(env: &HashMap<String, String>) -> Option<String>Expand description
Resolve the muxbus address (the agent’s display name) from a spawn env map.
AGENTMUX_AGENT_ID (= agent.name, set at block creation) is canonical;
WAVEMUX_AGENT_ID is the legacy fallback. Returns None — i.e. not
muxbus-addressable — when neither is present (a non-agent persistent block).