feat: 报表行类型模型完整接通-数据行绑定数据集自动扩展/汇总行聚合${字段:SUM|AVG|MIN|MAX|COUNT}/数据集前缀占位符${数据集.字段}/标题表头汇总行语义持久化/HTML+Excel共享渲染+设计器绑定数据集选择器与提示

Co-Authored-By: Claude Code <noreply@anthropic.com>

Author: pythonHuang

Juggle.Api/Controllers/Api/ReportController.cs

@@ -85,7 +85,7 @@ public async Task<IActionResult> ExportPdf([FromBody] ReportPreviewRequest req)
     {
         var rpt = await _db.Set<ReportEntity>().FindAsync(req.Id);
         if (rpt == null) return NotFound();
-        var data = _reportExec.ExportPdf(rpt.LayoutJson!, req.Params);
+        var data = await _reportExec.ExportPdfAsync(rpt.LayoutJson!, req.Params);
         return File(data, "text/html", $"{rpt.Name}.html");
     }
 
@@ -94,7 +94,7 @@ public async Task<IActionResult> ExportExcel([FromBody] ReportPreviewRequest req
     {
         var rpt = await _db.Set<ReportEntity>().FindAsync(req.Id);
         if (rpt == null) return NotFound();
-        var data = _reportExec.ExportExcel(rpt.LayoutJson!, req.Params);
+        var data = await _reportExec.ExportExcelAsync(rpt.LayoutJson!, req.Params);
         return File(data, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", $"{rpt.Name}.xlsx");
     }
 }