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/Spinners.java

@@ -0,0 +1,27 @@
+package com.ts3client.ui;
+
+import javax.swing.JSpinner;
+import java.awt.Dimension;
+
+/** Shared shaping for the numeric spinners the channel editor is full of. */
+final class Spinners {
+
+    /** Width that fits a five-digit power without swallowing the rest of a form row. */
+    private static final int WIDTH = 80;
+
+    private Spinners() {
+    }
+
+    /**
+     * Keeps a spinner to a sensible width and drops the grouping separator: these hold
+     * permission powers and client counts, which TeamSpeak shows as plain numbers.
+     */
+    static JSpinner compact(JSpinner spinner) {
+        JSpinner.NumberEditor editor = new JSpinner.NumberEditor(spinner, "#");
+        spinner.setEditor(editor);
+        Dimension size = new Dimension(WIDTH, spinner.getPreferredSize().height);
+        spinner.setPreferredSize(size);
+        spinner.setMaximumSize(size);
+        return spinner;
+    }
+}