Module serve 

SessionActor and LiveSessionRegistry for zeph serve (spec-068 §9, #5343).

Each live conversation-session under zeph serve is a SessionActor task: it owns an Agent<LoopbackChannel> exclusively, bridges SessionCommands into the agent’s channel input, and forwards the channel’s output as SessionOutput over a broadcast channel any number of HTTP/SSE or TUI attachments can subscribe to.

LiveSessionRegistry is pure bookkeeping (a HashMap behind a parking_lot::Mutex, never held across .await) — it does not itself supervise tasks. SessionActor::spawn registers a coordinator task under TaskSupervisor via spawn_oneshot(name: Arc<str>, factory) (architect ruling D-7): the dynamic serve.session.<id> name and non-restarting RunOnce policy are exactly right for a session actor (re-driving a torn turn/replay after a crash is unsafe; recovery is a fresh spawn that replays the durable log from the last committed seq).

Agent<C>’s futures are !Send (documented precedent: crates/zeph-acp/src/transport/ stdio.rs, “Agent futures are !Send and deeply nested”) and Agent<LoopbackChannel> itself cannot cross any thread boundary — not just spawn_oneshot’s Send bound but a std::thread::spawn one too. SessionActor::spawn resolves this exactly as zeph-acp’s serve_stdio/transport/http.rs do (architect ruling D-8): the Agent is constructed and driven entirely inside a dedicated OS thread with its own current_thread runtime and LocalSet — only Send-safe state (a FnOnce(LoopbackChannel) -> Agent<LoopbackChannel> factory, mirroring zeph-acp’s SendAgentSpawner) crosses into that thread. The spawn_oneshot task is a thin coordinator, never the agent driver itself: it awaits the thread’s completion signal and, on process-wide supervisor shutdown, forwards cancellation onto the session’s own CancellationToken (distinct from the supervisor’s) so idle eviction (spec §9.3) can cancel exactly one session without tearing down every live actor, while drive only ever needs to select on a single cancellation source regardless of trigger.

Structs

LiveSessionRegistry

Registry of live SessionActors for zeph serve (spec §9.3).

SessionActor

Owns a live Agent<LoopbackChannel> for one conversation-session (spec §9.2).

SessionActorHandle

Bookkeeping handle for one live session, held by LiveSessionRegistry (spec §9.3).

Enums

SessionCommand

A command sent to a live SessionActor (spec §9.2).

SessionOutput

An event streamed out of a live SessionActor (spec §9.2).