fix(quick-18): add group membership check to FloatingNodeHeader drag end

- Import defaultNodeDimensions for node sizing
- Capture wasDragging state before resetting ref
- Calculate node center using measured/default dimensions
- Check if node center is inside any group bounds
- Update groupId via setNodeGroupId if it changed
- Matches WorkflowCanvas handleNodeDragStop logic

Fixes bug where nodes dragged outside groups via floating header
were not removed from the group, causing them to still move when
the group was dragged.

src/components/nodes/FloatingNodeHeader.tsx

@@ -5,6 +5,7 @@ import { createPortal } from "react-dom";
 import { useReactFlow } from "@xyflow/react";
 import { NodeType } from "@/types";
 import { useWorkflowStore } from "@/store/workflowStore";
+import { defaultNodeDimensions } from "@/store/utils/nodeDefaults";
 
 export interface CommentNavigationProps {
   currentIndex: number;
@@ -263,9 +264,51 @@ export function FloatingNodeHeader({
     };
 
     const handlePointerUp = () => {
+      const wasDragging = isDraggingRef.current;
+
       document.removeEventListener('pointermove', handlePointerMove);
       document.removeEventListener('pointerup', handlePointerUp);
       isDraggingRef.current = false;
+
+      // Check group membership if the node was actually dragged
+      if (wasDragging) {
+        const store = useWorkflowStore.getState();
+        const allNodes = getNodes();
+        const draggedNode = allNodes.find(n => n.id === id);
+
+        if (!draggedNode) return;
+
+        // Get node dimensions (prefer measured, fallback to defaults)
+        const defaults = defaultNodeDimensions[type] || { width: 300, height: 280 };
+        const nodeWidth = draggedNode.measured?.width || (draggedNode.style?.width as number) || defaults.width;
+        const nodeHeight = draggedNode.measured?.height || (draggedNode.style?.height as number) || defaults.height;
+
+        // Calculate node center
+        const nodeCenterX = draggedNode.position.x + nodeWidth / 2;
+        const nodeCenterY = draggedNode.position.y + nodeHeight / 2;
+
+        // Check if node center is inside any group
+        let targetGroupId: string | undefined;
+
+        for (const group of Object.values(store.groups)) {
+          const inBoundsX = nodeCenterX >= group.position.x && nodeCenterX <= group.position.x + group.size.width;
+          const inBoundsY = nodeCenterY >= group.position.y && nodeCenterY <= group.position.y + group.size.height;
+
+          if (inBoundsX && inBoundsY) {
+            targetGroupId = group.id;
+            break;
+          }
+        }
+
+        // Get the node's current groupId
+        const currentNode = store.nodes.find((n) => n.id === id);
+        const currentGroupId = currentNode?.groupId;
+
+        // Update groupId if it changed
+        if (targetGroupId !== currentGroupId) {
+          store.setNodeGroupId(id, targetGroupId);
+        }
+      }
     };
 
     document.addEventListener('pointermove', handlePointerMove);