Move a client into your own channel from its context menu

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

ts3-client/swing/src/main/java/com/ts3client/ui/ServerTreePanel.java

@@ -57,6 +57,9 @@ public final class ServerTreePanel extends JScrollPane {
 
         void showConnectionInfo(ClientEntry client);
 
+        /** Moves a client into the channel we are currently in. */
+        void moveClientToOwnChannel(ClientEntry client);
+
         /** Open the file repository browser for a channel. */
         void browseFiles(ChannelNode channel);