chore: remove dead code and stale comments

- Drop dead Rooms/Room infrastructure and the rooms field on Context.
- Remove unused ActorMessage::Tick variant and the now-empty handler arm.
- Strip dead active-thread tracking machinery from ThreadPool (unused
  getters, _id/_active_threads/_total_threads parameters).
- Flatten ServerActor::initiate_connection: the duplicated retry block
  was a copy-paste retry against the same address with the same args
  and could never succeed where the first attempt failed.
- Delete commented-out print_hex2/decode debug stubs, dead test
  fixtures in login.rs and message_user.rs, the 47-line commented body
  of RoomListHandler, and assorted // TODO theater.

soulseek-rs-lib/src/message/server/message_user.rs

@@ -29,37 +29,3 @@ impl MessageHandler<ServerMessage> for MessageUser {
         user_message.print()
     }
 }
-
-// #[cfg(test)]
-// use std::sync::mpsc;
-// #[cfg(test)]
-// use std::sync::mpsc::{Receiver, Sender};
-//
-// #[test]
-// fn test_handle() {
-//     let (message_sender, _message_reader): (Sender<Message>, Receiver<Message>) = mpsc::channel();
-//
-//     let context = Arc::new(Mutex::new(Context::new(Arc::new(Mutex::new(
-//         message_sender,
-//     )))));
-//     let mut message = Message::new_with_data(vec![
-//         254, 0, 0, 0, 22, 0, 0, 0, 153, 102, 47, 0, 58, 65, 228, 102, 6, 0, 0, 0, 115, 101, 114,
-//         118, 101, 114, 227, 0, 0, 0, 89, 111, 117, 114, 32, 99, 111, 110, 110, 101, 99, 116, 105,
-//         111, 110, 32, 105, 115, 32, 114, 101, 115, 116, 114, 105, 99, 116, 101, 100, 58, 32, 89,
-//         111, 117, 32, 99, 97, 110, 110, 111, 116, 32, 115, 101, 97, 114, 99, 104, 32, 111, 114, 32,
-//         99, 104, 97, 116, 46, 32, 89, 111, 117, 114, 32, 99, 108, 105, 101, 110, 116, 32, 118, 101,
-//         114, 115, 105, 111, 110, 32, 105, 115, 32, 116, 111, 111, 32, 111, 108, 100, 46, 32, 89,
-//         111, 117, 32, 110, 101, 101, 100, 32, 116, 111, 32, 117, 112, 103, 114, 97, 100, 101, 32,
-//         116, 111, 32, 116, 104, 101, 32, 108, 97, 116, 101, 115, 116, 32, 118, 101, 114, 115, 105,
-//         111, 110, 46, 32, 67, 108, 111, 115, 101, 32, 116, 104, 105, 115, 32, 99, 108, 105, 101,
-//         110, 116, 44, 32, 100, 111, 119, 110, 108, 111, 97, 100, 32, 110, 101, 119, 32, 118, 101,
-//         114, 115, 105, 111, 110, 32, 102, 114, 111, 109, 32, 104, 116, 116, 112, 58, 47, 47, 119,
-//         119, 119, 46, 115, 108, 115, 107, 110, 101, 116, 46, 111, 114, 103, 44, 32, 105, 110, 115,
-//         116, 97, 108, 108, 32, 105, 116, 32, 97, 110, 100, 32, 114, 101, 99, 111, 110, 110, 101,
-//         99, 116, 46, 1,
-//     ]);
-//     message.set_pointer(8);
-//     MessageUser.handle(&mut message.clone(), context.clone());
-//     assert_eq!(1, context.lock().unwrap().get_user_messages().len());
-// }
-// // }