add back vector to shape

src/folk-shape.ts

@@ -347,6 +347,22 @@ export class FolkShape extends HTMLElement {
         // Get the corner coordinates of the shape for the corresponding handle
         const rect = this.#rect;
 
+        let vector: Point;
+        switch (event.key) {
+          case 'ArrowUp':
+            vector = { x: 0, y: -MOVEMENT_DELTA };
+            break;
+          case 'ArrowDown':
+            vector = { x: 0, y: MOVEMENT_DELTA };
+            break;
+          case 'ArrowLeft':
+            vector = { x: -MOVEMENT_DELTA, y: 0 };
+            break;
+          case 'ArrowRight':
+            vector = { x: MOVEMENT_DELTA, y: 0 };
+            break;
+        }
+
         // Map handle names to corner points
         const HANDLE_TO_CORNER: Record<string, Point> = {
           'resize-top-left': rect.topLeft,