- Replace the axum/tungstenite pump paths' Notify-based read-EOF signal
with a retained tokio watch channel: a late subscriber (monitor
spawned after session setup, or pump EOF before the receiver is
taken) still observes EOF (WS-02).
- from_wss drop monitor: on EOF (or session close) fail all pendings
retryable, then keep sweeping the pending map every 1 s — calls
registered after the initial fail_all (the forgotten-session import
path) resolve instead of hanging (CON-02).
- Tests: drop-during-registration race variants (forget + held
session) and a post-EOF registration resolved via the sweep; the
existing no-hang test stays green.
cargo test (219), cargo test --features wss (231, 3x for flake check),
cargo clippy --all-targets -- -D warnings, cargo fmt --check