- AcceptFn: the injected accepted-connection source (the assembly
layer owns the listener + accept loop; the protocol never binds —
OQ-TN-04).
- AcceptQueue: the protocol-side queue contract (async push/pop/
close; FIFO always-before-take ordering; close-while-waiting
resolves None). Empty-queue posture is assembly-owned (a late
accept is legitimate; resource_shortage is the closure's mapping;
the wrapper's 10s establishment timeout is the backstop).
- listen_establisher: same open op, same params, same typed errors —
registry namespace gate → accept() → Establishment::new(plan);
the pump handler is untouched (plan-flow with a different source).
- register_tunnel_listen_openable: same spec/pump registration with
the listen establisher (the honest shape vs a dial/accept enum:
the establisher is the only difference; one establisher per op id
per session registry — documented).
- Tests (tests/producer_listen.rs, 6): listen flow end-to-end, FIFO
ordering across two opens (R-01 plan-flow, listen-flavored), empty
queue -> resource_shortage, closed listener -> dial_failed,
unknown resource -> unknown_resource, late-push wait-then-resolve.
- Harness: RegistrationMode enum + wire_listen.
- TargetHandle gains a structural Debug impl (test ergonomics).
Verified: cargo test green (44), clippy -D warnings (native + wasm32),
fmt clean, wasm32 check passes.