fix: GetPortfolios 返回格式修正为 { items: [...] }

前端期望 data 是对象而非数组

AssetManager.API/Controllers/PortfolioController.cs

@@ -65,15 +65,18 @@ public class PortfolioController : ControllerBase
     /// 获取投资组合列表
     /// </summary>
     [HttpGet]
-    public async Task<ActionResult<ApiResponse<List<PortfolioListItem>>>> GetPortfolios()
+    public async Task<ActionResult<ApiResponse<GetPortfoliosResponse>>> GetPortfolios()
     {
         var userId = GetCurrentUserId();
         var portfolios = await _portfolioFacade.GetPortfolioListAsync(userId);
         
-        return Ok(new ApiResponse<List<PortfolioListItem>>
+        return Ok(new ApiResponse<GetPortfoliosResponse>
         {
             code = Models.StatusCodes.Success,
-            data = portfolios,
+            data = new GetPortfoliosResponse
+            {
+                Items = portfolios
+            },
             message = "success"
         });
     }