refactor: resolve all lint findings

- remove 34 trivial restating comments (auto-fix)
- replace all 20 production .unwrap() calls with graceful handling:
  ?-propagation via LockPoisoned, unwrap_or_default on infallible
  conversions, let _ = on actor-channel sends, and a downloads_sender()
  helper in the TUI that also dedupes three channel-init blocks
- collapse nested if into match guard (clippy::collapsible_match)
- split client.rs (2275 lines) into a client/ module: connection,
  search, downloads, uploads, rooms, operations
- split ui/main_tui.rs (2027 lines) into a main_tui/ module: render,
  input, browse, rooms, downloads, search
- extract oversized functions: peer_actor/server_actor handle_message
  into per-message helpers, main() into init_logging/run_default_tui,
  download_selector and main_tui render into per-section helpers

Mechanical only, zero behavior change. Verified: clippy clean
(pedantic+nursery), fmt clean, 143 unit tests + 16 e2e tests against
soulfind pass, lint clean.

soulseek-rs-lib/src/message/mod.rs

@@ -57,10 +57,8 @@ impl Message {
 
         let chunks = data.chunks(BYTES_PER_LINE);
         for (i, chunk) in chunks.enumerate() {
-            // Print the offset
             print!("{:04x}  ", i * BYTES_PER_LINE);
 
-            // Print the hexadecimal part
             for j in 0..BYTES_PER_LINE {
                 if j < chunk.len() {
                     print!("{:02x} ", chunk[j]);
@@ -76,7 +74,6 @@ impl Message {
 
             print!("  ");
 
-            // Print the ASCII part
             let mut i = 0;
             for &byte in chunk {
                 i += 1;
@@ -101,7 +98,7 @@ impl Message {
         if self.data.len() < 8 {
             return 0;
         }
-        u32::from_le_bytes(self.data[4..8].try_into().unwrap())
+        self.data[4..8].try_into().map_or(0, u32::from_le_bytes)
     }
 
     #[must_use]

soulseek-rs-lib/src/message/peer/file_search_response.rs

@@ -59,9 +59,7 @@ impl MessageHandler<PeerMessage> for FileSearchResponse {
             return;
         };
 
-        sender
-            .send(PeerMessage::FileSearchResult(file_search))
-            .unwrap();
+        let _ = sender.send(PeerMessage::FileSearchResult(file_search));
     }
 }
 

soulseek-rs-lib/src/message/peer/peer_init.rs

@@ -23,6 +23,6 @@ impl MessageHandler<PeerMessage> for PeerInit {
             username, connection_type, token
         );
 
-        sender.send(PeerMessage::SetUsername(username)).unwrap();
+        let _ = sender.send(PeerMessage::SetUsername(username));
     }
 }

soulseek-rs-lib/src/message/peer/place_in_queue_response.rs

@@ -15,8 +15,7 @@ impl MessageHandler<PeerMessage> for PlaceInQueueResponse {
         let filename = message.read_string();
         let place = message.read_int32();
 
-        sender
-            .send(PeerMessage::PlaceInQueueResponse { filename, place })
-            .unwrap();
+        let _ =
+            sender.send(PeerMessage::PlaceInQueueResponse { filename, place });
     }
 }

soulseek-rs-lib/src/message/peer/transfer_request.rs

@@ -13,6 +13,6 @@ impl MessageHandler<PeerMessage> for TransferRequest {
     fn handle(&self, message: &mut Message, sender: Sender<PeerMessage>) {
         let transfer = Transfer::new_from_message(message);
 
-        sender.send(PeerMessage::TransferRequest(transfer)).unwrap();
+        let _ = sender.send(PeerMessage::TransferRequest(transfer));
     }
 }

soulseek-rs-lib/src/message/peer/transfer_response.rs

@@ -16,12 +16,10 @@ impl MessageHandler<PeerMessage> for TransferResponse {
         let allowed = message.read_int8();
         let reason = (allowed == 0).then(|| message.read_string());
 
-        sender
-            .send(PeerMessage::TransferResponse {
-                token,
-                allowed: allowed == 1,
-                reason,
-            })
-            .unwrap();
+        let _ = sender.send(PeerMessage::TransferResponse {
+            token,
+            allowed: allowed == 1,
+            reason,
+        });
     }
 }

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

@@ -24,14 +24,12 @@ impl MessageHandler<ServerMessage> for GetPeerAddressHandler {
         let obfuscated_port = message.read_int32() as u16;
         crate::debug!("GetPeerAddressHandler: {username:?}");
 
-        sender
-            .send(ServerMessage::GetPeerAddressResponse {
-                username,
-                host,
-                port,
-                obfuscation_type,
-                obfuscated_port,
-            })
-            .unwrap();
+        let _ = sender.send(ServerMessage::GetPeerAddressResponse {
+            username,
+            host,
+            port,
+            obfuscation_type,
+            obfuscated_port,
+        });
     }
 }

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

@@ -16,13 +16,14 @@ impl MessageHandler<ServerMessage> for LoginHandler {
         let response = message.read_int8();
 
         if response != 1 {
-            return sender.send(ServerMessage::LoginStatus(false)).unwrap();
+            let _ = sender.send(ServerMessage::LoginStatus(false));
+            return;
         }
 
         info!("Login successful");
         let greeting = message.read_string();
         debug!("Server greeting: {:?}", greeting);
 
-        sender.send(ServerMessage::LoginStatus(true)).unwrap();
+        let _ = sender.send(ServerMessage::LoginStatus(true));
     }
 }