get group resize, enter and exit working

frontend/src/groupDrag.js

@@ -0,0 +1,18 @@
+export const GROUP_DRAG_RELEASE_DISTANCE = 18;
+
+export function getPointDistanceOutsideRect(rect, point) {
+  if (!rect || !point) return Infinity;
+
+  const dx = point.x < rect.left
+    ? rect.left - point.x
+    : (point.x > rect.right ? point.x - rect.right : 0);
+  const dy = point.y < rect.top
+    ? rect.top - point.y
+    : (point.y > rect.bottom ? point.y - rect.bottom : 0);
+
+  return Math.hypot(dx, dy);
+}
+
+export function shouldReleaseFromGroup(rect, point, threshold = GROUP_DRAG_RELEASE_DISTANCE) {
+  return getPointDistanceOutsideRect(rect, point) >= threshold;
+}