Replace grid hack with FlexBox for GoodButtons

gui/ui/app.slint

@@ -186,19 +186,21 @@ component GoodButtons inherits ScrollView {
 
     property <int> count-x: floor(root.width / (button-min-width + button-spacing));
     property <int> count-y: ceil(State.favorites.length / count-x);
-    property <length> button-width: ((self.width + button-spacing) / count-x) - button-spacing;
+    property <length> button-width: ((root.width + button-spacing) / count-x) - button-spacing;
 
     content-height: (count-y * (button-height + button-spacing));
     mouse-drag-pan-enabled: true;
+    vertical-scrollbar-policy: always-off;
 
-    for item[idx] in State.favorites: Button {
-        x: floor(mod(idx, count-x)) * (root.button-width + root.button-spacing);
-        y: floor(idx / count-x) * (root.button-height + root.button-spacing);
-        width: root.button-width;
-        height: root.button-height;
-        text: item.name;
-        clicked => {
-            State.add-to-list(item.name);
+    FlexboxLayout {
+        spacing: button-spacing;
+        for item in State.favorites: Button {
+            width: root.button-width;
+            height: root.button-height;
+            text: item.name;
+            clicked => {
+                State.add-to-list(item.name);
+            }
         }
     }
 }