Add the Edit Channel dialog

Recovers the official client's CreateChannelDialog layout so the widget
set, labels and tab order match: name/icon/password/topic/description
above Standard, Audio, Permissions and Advanced tabs.

Core gains ChannelSettings (diffed against the original so channeledit
only carries changed properties) and ChannelAdmin (channelinfo/edit,
channel permissions, the server icon store). TeamspeakConnection now
owns the event executor so it can drain queued notify events before
reading a command's result, which channelpermlist needs.

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

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

@@ -44,6 +44,9 @@ public final class ServerTreePanel extends JScrollPane {
         /** Moves a client into the channel we are currently in. */
         void moveClientToOwnChannel(ClientEntry client);
 
+        /** Opens the channel editor for a channel. */
+        void editChannel(ChannelNode channel);
+
         /** Open the file repository browser for a channel. */
         void browseFiles(ChannelNode channel);