fix: create new canvas instead of redirecting when canvas not found

app/canvas/[id]/page.tsx

@@ -142,8 +142,15 @@ export default function CanvasEditorPage({ params }: PageProps) {
           loadCanvas(result.data.canvasData);
         }
       } else {
-        toast.error(result.error || "加载画布失败");
-        router.push("/canvas");
+        // 画布不存在时，创建一个新画布
+        console.log('画布不存在，创建新画布:', id);
+        setProject(id, '未命名画布');
+        // 保存新画布到数据库
+        try {
+          await canvasService.saveCanvasState(id, { nodes: [], connections: [] });
+        } catch (error) {
+          console.error('创建新画布失败:', error);
+        }
       }
       setIsLoading(false);
     };

components/canvas/CanvasChatPanel.tsx

@@ -327,27 +327,22 @@ export function CanvasChatPanel({ chatId, initialMessages = [], onClose, onOpenF
           <Button variant="ghost" size="icon" className="h-8 w-8 rounded-full hover:bg-muted">
             <Share2 className="h-4 w-4" />
           </Button>
-          <button 
-            type="button"
-            className="h-10 w-10 rounded-full inline-flex items-center justify-center bg-red-500 text-white border-4 border-yellow-400 animate-pulse relative z-[9999]"
-            onMouseDown={(e) => {
-              e.preventDefault();
-              e.stopPropagation();
-              alert('🎯 MouseDown! onOpenFileList: ' + !!onOpenFileList);
-            }}
+          <Button 
+            variant="ghost" 
+            size="icon" 
+            className="h-8 w-8 rounded-full hover:bg-muted"
             onClick={(e) => {
               e.preventDefault();
               e.stopPropagation();
-              alert('🎯 Click! onOpenFileList: ' + !!onOpenFileList);
-              console.log('[CanvasChatPanel] File list button clicked, onOpenFileList:', !!onOpenFileList);
+              console.log('[CanvasChatPanel] File list button clicked');
               if (onOpenFileList) {
                 onOpenFileList();
               }
             }}
-            title="文件列表按钮 - 点我切换到文件列表"
+            title="已生成文件列表"
           >
-            <LayoutGrid className="h-5 w-5" />
-          </button>
+            <LayoutGrid className="h-4 w-4" />
+          </Button>
           <Button variant="ghost" size="icon" className="h-8 w-8 rounded-full hover:bg-muted">
             <Maximize2 className="h-4 w-4" />
           </Button>