feat(protocol): interests, tickers, global room and cant-connect

Adds the server messages the client had no way to speak: user and room
search (42/120), room tickers (113-116), the global room feed (150-152),
interests and the recommendation queries built on them (51/52/54/56/57/
110/111/112/117/118), a keepalive ping (32), gifted privileges (123), a
password change (142) and multi-user private messages (149).

CantConnectToPeer (1001) closes a real gap in both directions: a dial the
server asked us to make now answers the waiting peer instead of falling
back to brokering the same unreachable link the other way, and an incoming
one ends the wait on downloads queued for that peer rather than letting
them sit until a timeout.

soulseek-rs-lib/src/actor/peer_actor/tests.rs

@@ -50,7 +50,7 @@ fn a_timed_out_connect_parks_the_actor_in_disconnected() {
         "a timed-out connect must leave Connecting"
     );
     match rx.try_recv() {
-        Ok(ClientOperation::PeerConnectFailed(7, username)) => {
+        Ok(ClientOperation::PeerConnectFailed(7, username, _)) => {
             assert_eq!(username, "bob");
         }
         other => panic!("expected PeerConnectFailed, got {other:?}"),