Integrate the menu button in the search box

Allows us to make the search box wider, too

app/components/app-header.gjs

@@ -24,16 +24,7 @@ export default class AppHeaderComponent extends Component {
   <template>
     <header class="app-header">
       <div class="header-left">
-        <button
-          class="menu-btn btn-press"
-          type="button"
-          aria-label="Menu"
-          {{on "click" @onToggleMenu}}
-        >
-          <Icon @name="menu" @size={{24}} @color="#333" />
-        </button>
-
-        <SearchBox />
+        <SearchBox @onToggleMenu={{@onToggleMenu}} />
       </div>
 
       <div class="header-right">