feat(canvas): 完善画布 Agent 交互能力

web/src/pages/canvas/project.tsx

@@ -1511,7 +1511,7 @@ function InfiniteCanvasPage() {
     const canCreateDrawingFromConnection = !pendingConnectionCreate?.batchSourceNodeIds?.length && pendingConnectionSourceNode?.type === CanvasNodeType.Image && Boolean(pendingConnectionSourceNode.metadata?.content);
 
     const openTextNodeEditor = useCallback((node: CanvasNodeData) => {
-        if (node.type !== CanvasNodeType.Text) return;
+        if (node.type !== CanvasNodeType.Text && node.type !== CanvasNodeType.Markdown) return;
         setSelectedNodeIds(new Set([node.id]));
         setSelectedConnectionId(null);
         setContextMenu(null);