Zoom chat and descriptions with Ctrl+mouse wheel

Text and pictures in the chat tabs and the info panel zoom in browser
steps (50-300 %), keeping the line at the top in view. The chat and the
info panel each have their own level, shared by every server tab and
saved in the settings.

The HTML documents now take their fonts from a stylesheet that applies
the zoom. The old ScaledStyleSheet never reached the document, and
FlatLaf already applies the interface scale, so it only zooms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ts3-client/core/src/main/java/com/ts3client/config/Settings.java

@@ -198,6 +198,10 @@ public final class Settings {
     public String chatLogDir = "";
     /** Whether descriptions show their pictures, fetched from the web, or only links to them. */
     public boolean descriptionPictures = true;
+    /** Ctrl+wheel zoom of the chat's text and pictures, 1.0 being 100 %. */
+    public double chatZoom = 1.0;
+    /** Ctrl+wheel zoom of the info panel's text and pictures, 1.0 being 100 %. */
+    public double infoZoom = 1.0;
 
     public static Settings load() {
         Settings s = new Settings();