fix: Neuer Chat Button erstellt Session, Ordner drag&drop im KI-Baum

frontend/src/components/ai/SessionList.tsx

@@ -43,7 +43,7 @@ function buildTree(folders: ChatFolder[], sessions: ChatSession[]): TreeNode[] {
 }
 
 function TreeItem({
-  node, activeSessionId, onSelectSession, depth, onContextMenu, onDragSession, onDropToFolder, onDelete,
+  node, activeSessionId, onSelectSession, depth, onContextMenu, onDragSession, onDragFolder, onDropToFolder, onDelete,
 }: {
   node: TreeNode;
   activeSessionId: string | null;
@@ -51,6 +51,7 @@ function TreeItem({
   depth: number;
   onContextMenu: (e: React.MouseEvent, type: 'session' | 'folder' | 'root', id: string | null) => void;
   onDragSession: (sessionId: string) => void;
+  onDragFolder: (folderId: string) => void;
   onDropToFolder: (folderId: string | null) => void;
   onDelete: (id: string, type: 'session' | 'folder') => void;
 }) {
@@ -63,7 +64,15 @@ function TreeItem({
     e.preventDefault();
     e.stopPropagation();
     setIsDragOver(false);
+    const data = e.dataTransfer.getData('text/plain');
+    if (data.startsWith('folder:')) {
+      const draggedFolderId = data.slice(7);
+      if (draggedFolderId !== folderId) {
         onDropToFolder(folderId);
+      }
+    } else {
+      onDropToFolder(folderId);
+    }
   };
 
   const handleDragOver = (e: React.DragEvent) => {
@@ -77,6 +86,12 @@ function TreeItem({
       {/* Folder header - drop target */}
       {!isRoot && (
         <div
+          draggable
+          onDragStart={(e) => {
+            e.dataTransfer.setData('text/plain', `folder:${node.folder!.id}`);
+            e.dataTransfer.effectAllowed = 'move';
+            onDragFolder(node.folder!.id);
+          }}
           onDragOver={handleDragOver}
           onDragLeave={() => setIsDragOver(false)}
           onDrop={handleDrop}
@@ -166,6 +181,7 @@ function TreeItem({
           depth={depth + 1}
           onContextMenu={onContextMenu}
           onDragSession={onDragSession}
+          onDragFolder={onDragFolder}
           onDropToFolder={onDropToFolder}
           onDelete={onDelete}
         />
@@ -236,6 +252,7 @@ export function SessionList({ activeSessionId, onSelectSession, isSidebar, class
   const [loading, setLoading] = useState(true);
   const [error, setError] = useState<string | null>(null);
   const [dragSessionId, setDragSessionId] = useState<string | null>(null);
+  const [dragFolderId, setDragFolderId] = useState<string | null>(null);
   const [contextMenu, setContextMenu] = useState<ContextMenuState | null>(null);
 
   const loadData = async () => {
@@ -296,6 +313,14 @@ export function SessionList({ activeSessionId, onSelectSession, isSidebar, class
   };
 
   const handleDropToFolder = async (folderId: string | null) => {
+    if (dragFolderId) {
+      try {
+        await updateFolder(dragFolderId, { parent_id: folderId });
+        setDragFolderId(null);
+        loadData();
+      } catch (e) { setError(e instanceof Error ? e.message : 'Failed to move folder'); }
+      return;
+    }
     if (!dragSessionId) return;
     try {
       await updateSession(dragSessionId, { folder_id: folderId });
@@ -326,6 +351,7 @@ export function SessionList({ activeSessionId, onSelectSession, isSidebar, class
             depth={0}
             onContextMenu={handleContextMenu}
             onDragSession={setDragSessionId}
+            onDragFolder={setDragFolderId}
             onDropToFolder={handleDropToFolder}
             onDelete={handleDelete}
           />

frontend/src/pages/AIAssistant.tsx

@@ -3,7 +3,7 @@ import { SessionList } from '@/components/ai/SessionList';
 import { ChatWindow } from '@/components/ai/ChatWindow';
 import { ResizablePanel } from '@/components/ui/ResizablePanel';
 import { usePluginToolbarStore } from '@/store/pluginToolbarStore';
-import { fetchAgents, type AIAgent } from '@/api/ai';
+import { fetchAgents, createSession, type AIAgent } from '@/api/ai';
 
 export function AIAssistantPage() {
   const [activeSessionId, setActiveSessionId] = useState<string | null>(null);
@@ -39,7 +39,16 @@ export function AIAssistantPage() {
             <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 4v16m8-8H4" />
           </svg>
         ),
-        onClick: () => { setActiveSessionId(null); setMobileView('list'); setRefreshKey(k => k + 1); },
+        onClick: async () => {
+          try {
+            const session = await createSession({ is_sidebar: false });
+            setActiveSessionId(session.id);
+            setMobileView('chat');
+            setRefreshKey(k => k + 1);
+          } catch (e) {
+            console.error('Failed to create session:', e);
+          }
+        },
       },
       {
         id: 'new-folder',