Use one button style and an icon-only dock

Buttons no longer have a primary style: every button is the translucent
outlined surface that brightens on hover, and only an icon button's icon
takes the accent color. The title screen's dock shows just its icons.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/main/java/org/saturnclient/ui/elements/IconButton.java

@@ -7,8 +7,8 @@ import org.saturnclient.ui.ElementContext;
 import org.saturnclient.ui.RenderScope;
 
 /**
- * A square secondary {@link Button} showing an icon, which turns the accent
- * color on hover.
+ * A square {@link Button} showing an icon, which turns the accent color on
+ * hover.
  */
 public class IconButton extends Element {
     private static final float ICON_RATIO = 0.48f;
@@ -26,7 +26,7 @@ public class IconButton extends Element {
     @Override
     public void render(RenderScope renderScope, ElementContext ctx) {
         boolean hovered = ctx.isHovering();
-        Button.drawSurface(renderScope, width, height, false, hovered);
+        Button.drawSurface(renderScope, width, height, hovered);
 
         int size = (int) (Math.min(width, height) * ICON_RATIO);
         renderScope.drawTexture(icon, (width - size) / 2, (height - size) / 2, 0, 0, size, size,