feat: Add compact view option to preferences

The code changes introduce a new preference option for enabling the compact view in the Zen browser. This allows users to show only the toolbars they use, improving the browsing experience for those who prefer a minimalistic interface.

(closes #31)

src/browser/components/preferences/zen-looks.js

@@ -59,4 +59,9 @@ Preferences.addAll([
     type: "bool",
     default: true,
   },
+  {
+    id: "zen.view.compact",
+    type: "bool",
+    default: false,
+  },
 ]);

src/browser/components/preferences/zenLooksAndFeel.inc.xhtml

@@ -17,6 +17,13 @@
       <checkbox id="zenLooksAndFeelUseThemedToolbar"
             data-l10n-id="zen-look-and-feel-themed-toolbar"
             preference="zen.theme.toolbar-themed"/>
+
+      <label><html:h2 data-l10n-id="zen-look-and-feel-compact-view-header"/></label>
+      <description class="description-deemphasized" data-l10n-id="zen-look-and-feel-compact-view-description" />
+
+      <checkbox id="zenLooksAndFeelUseThemedToolbar"
+            data-l10n-id="zen-look-and-feel-compact-view-enabled"
+            preference="zen.view.compact"/>
 </groupbox>
 
 <hbox id="zenSidePanelsCategory"