feat(sts-viewer): add item rotation support in inventory

Introduces the ability to rotate inventory items using the Alt button
during drag-and-drop.

- Updates `InventoryItemContainer` to handle rotation via
  `previewRotation`
- Adds `newRotation` parameter to `onMoveItem` callback and `moveItem`
  command
- Updates `InventoryItemState` to manage rotation state and compute
  transformed shapes
- Implements rotation logic in `renderGraphics` using `transformShape`

packages/sts-like-viewer/src/scenes/InventoryTestScene.ts

@@ -93,8 +93,19 @@ export class InventoryTestScene extends ReactiveScene {
       this.gridOffsetX,
       this.gridOffsetY,
       {
-        onMoveItem: (itemId: string, newX: number, newY: number) => {
-          return moveItem(this.inventorySignal, itemId, newX, newY);
+        onMoveItem: (
+          itemId: string,
+          newX: number,
+          newY: number,
+          newRotation: number,
+        ) => {
+          return moveItem(
+            this.inventorySignal,
+            itemId,
+            newX,
+            newY,
+            newRotation,
+          );
         },
       },
     );