Fix multiplayer chat room signal disconnection and cleanup

- Add Shutdown() method to ChatRoom to properly disconnect Qt signals
- Initialize room_network pointer to nullptr for safety
- Call Shutdown() in MultiplayerRoomOverlay::DisconnectFromRoom() to prevent
  signal leaks when disconnecting from rooms
- Ensures proper cleanup of chat widget connections when overlay is hidden

Signed-off-by: Zephyron <zephyron@citron-emu.org>

src/citron/multiplayer/chat_room.cpp

@@ -221,6 +221,22 @@ void ChatRoom::Initialize(Network::RoomNetwork* room_network_) {
     }
 }
 
+void ChatRoom::Shutdown() {
+    if (room_network) {
+        // Disconnect the signals that were connected in Initialize.
+        // It's safe to call disconnect even if the connection doesn't exist.
+        disconnect(this, &ChatRoom::ChatReceived, this, &ChatRoom::OnChatReceive);
+        disconnect(this, &ChatRoom::StatusMessageReceived, this, &ChatRoom::OnStatusMessageReceive);
+
+        // NOTE: The Bind... functions do not have a direct unbind. The intended way
+        // to stop them is to let the 'member' object be destroyed or to stop calling them
+        // from the network backend. Since we are disconnecting from the room, this is safe.
+        // The important part is disconnecting the Qt signals.
+
+        room_network = nullptr; // Clear the pointer to prevent further use.
+    }
+}
+
 void ChatRoom::SetModPerms(bool is_mod) {
     has_mod_perms = is_mod;
 }

src/citron/multiplayer/chat_room.h

@@ -32,6 +32,7 @@ class ChatRoom : public QWidget {
 public:
     explicit ChatRoom(QWidget* parent);
     void Initialize(Network::RoomNetwork* room_network);
+    void Shutdown();
     void RetranslateUi();
     void SetPlayerList(const Network::RoomMember::MemberList& member_list);
     void Clear();
@@ -68,7 +69,7 @@ private:
     std::unique_ptr<Ui::ChatRoom> ui;
     std::unordered_set<std::string> block_list;
     std::unordered_map<std::string, QPixmap> icon_cache;
-    Network::RoomNetwork* room_network;
+    Network::RoomNetwork* room_network = nullptr; // Initialize to nullptr
 };
 
 Q_DECLARE_METATYPE(Network::ChatEntry);

src/citron/util/multiplayer_room_overlay.cpp

@@ -188,6 +188,12 @@ void MultiplayerRoomOverlay::ConnectToRoom() {
 }
 
 void MultiplayerRoomOverlay::DisconnectFromRoom() {
+    // Tell the chat widget to disconnect its signals *before*
+    // we reset our own state.
+    if (is_chat_initialized && chat_room_widget) {
+        chat_room_widget->Shutdown();
+    }
+
     ClearUI();
     room_member.reset();
     multiplayer_state = nullptr;