refactor: 移除 calculateDailyNav 接口

前端暂不需要，后续有需求再加

AssetManager.API/Controllers/PortfolioController.cs

@@ -272,16 +272,25 @@ public class PortfolioController : ControllerBase
     /// <summary>
     /// 创建交易（买入/卖出）
     /// </summary>
-    [HttpPost("{id}/transactions")]
+    [HttpPost("transactions")]
     public async Task<ActionResult<ApiResponse<TransactionItem>>> CreateTransaction(
-        string id,
         [FromBody] CreateTransactionRequest request)
     {
         var userId = GetCurrentUserId();
         
+        if (string.IsNullOrEmpty(request.PortfolioId))
+        {
+            return BadRequest(new ApiResponse<TransactionItem>
+            {
+                code = Models.StatusCodes.BadRequest,
+                data = null,
+                message = "portfolioId 不能为空"
+            });
+        }
+        
         try
         {
-            var transaction = await _portfolioFacade.CreateTransactionAsync(id, request, userId);
+            var transaction = await _portfolioFacade.CreateTransactionAsync(request.PortfolioId, request, userId);
             return Ok(new ApiResponse<TransactionItem>
             {
                 code = Models.StatusCodes.Success,