style: apply spotless (trim whitespace, unused imports)

src/main/java/dev/loki/loparkour/menu/gui/MenuItem.java

@@ -8,11 +8,11 @@ import org.jetbrains.annotations.NotNull;
  */
 public class MenuItem {
     private final ItemStack item;
-    
+
     public MenuItem(@NotNull ItemStack item) {
         this.item = item;
     }
-    
+
     public ItemStack getItem() {
         return item;
     }

src/main/java/dev/loki/loparkour/menu/gui/SliderItem.java

@@ -8,11 +8,11 @@ import java.util.function.Consumer;
  * Temporary stub for SliderItem during migration
  */
 public class SliderItem {
-    
+
     public SliderItem initial(int value) {
         return this;
     }
-    
+
     public SliderItem add(int index, Item item, Consumer<InventoryClickEvent> handler) {
         return this;
     }