Merge branch 'refactor-transport' into refactor-next

Forward-merge the transport neighbor-beacon rename (ethernet + BLE
discovery -> neighbor module/buffer rename; ethernet config discovery
flag -> listen with serde alias). Hand-resolved the module files against
next's identity-out-of-beacon beacon rewrite by starting from next's
bodies and re-applying the rename by identifier, so next's beacon logic
(no-arg build_beacon, bool parse_beacon, computed BEACON_SIZE, one-arg
add_peer, deleted BLE add_peer_with_pubkey) is preserved unchanged.

src/node/tests/ethernet.rs

@@ -83,7 +83,7 @@ async fn make_test_node_ethernet(interface: &str) -> TestNode {
 
     let config = EthernetConfig {
         interface: interface.to_string(),
-        discovery: Some(false),
+        listen: Some(false),
         announce: Some(false),
         accept_connections: Some(true),
         ..Default::default()