Merge branch 'refactor-node' into refactor-node-next

Re-express the handshake-state carrier collapse onto the XX code: the leg's
handshake_state field is deleted and the displayed state is derived from the
peer machine's phase, with failure carried on the machine (a send_failed flag
that preserves the handshake phase) rather than on the leg. The next projection
maps the SentMsg2 responder phase to received_msg1 and the anonymous-dial
Discovered phase to sent_msg1; the three initiator send-failure sites carry
failure via send_failed. Telemetry strings, wire bytes, index allocation, and
stale-connection reaping are byte-identical to next.

src/control/queries.rs

@@ -1320,7 +1320,7 @@ pub fn show_connections(node: &Node) -> Value {
             let mut conn_json = json!({
                 "link_id": conn.link_id().as_u64(),
                 "direction": format!("{}", conn.direction()),
-                "handshake_state": format!("{}", conn.handshake_state()),
+                "handshake_state": node.connection_handshake_state(conn.link_id()),
                 "started_at_ms": conn.started_at(),
                 "idle_ms": now.saturating_sub(conn.last_activity()),
                 "resend_count": node.connection_resend_count(conn.link_id()),