fix(workspace): reliably clear drag states on drop and dragend

frontend/src/features/workspace/WorkspaceView.tsx

@@ -579,8 +579,25 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
     await persistDocument(updatedDoc);
   };
 
+  // Global drag cleanup so drag states never get stuck if dragend is lost during re-render
+  useEffect(() => {
+    const handleGlobalDragEnd = () => {
+      setDraggingDocId(null);
+      setDragOverFolder(null);
+      setDraggingBlockId(null);
+    };
+    window.addEventListener('dragend', handleGlobalDragEnd);
+    window.addEventListener('drop', handleGlobalDragEnd);
+    return () => {
+      window.removeEventListener('dragend', handleGlobalDragEnd);
+      window.removeEventListener('drop', handleGlobalDragEnd);
+    };
+  }, []);
+
   const handleDropDocToFolder = async (folderPath: string, e: React.DragEvent) => {
     const docId = e.dataTransfer.getData('application/mindsift-doc-id') || draggingDocId;
+    setDraggingDocId(null);
+    setDragOverFolder(null);
     if (!docId) return;
     const doc = docs.find((d) => d.id === docId);
     if (!doc) return;
@@ -1244,6 +1261,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
           e.preventDefault();
           e.stopPropagation();
           setDragOverFolder(null);
+          setDraggingDocId(null);
           handleDropDocToFolder(node.path, e);
         }}
       >
@@ -1532,6 +1550,7 @@ export const WorkspaceView: React.FC<WorkspaceViewProps> = ({
                       e.preventDefault();
                       e.stopPropagation();
                       setDragOverFolder(null);
+                      setDraggingDocId(null);
                       handleDropDocToFolder('', e);
                     }}
                     className={`mx-2 my-1.5 p-2 border-2 border-dashed rounded-btn text-center text-xs transition-colors ${