fix: EditPlanResponse暴露result_count字段（列表/详情接口）

apps/api/app/api/routes/edit_plans.py

@@ -72,6 +72,7 @@ class EditPlanResponse(BaseModel):
     name: str
     status: str
     total_duration: float
+    result_count: int = 0
     project_id: str = ""
     created_by_user_id: str = ""
     config: dict[str, Any]
@@ -241,6 +242,7 @@ def _to_response(p: EditPlan) -> EditPlanResponse:
         name=p.name,
         status=p.status.value if hasattr(p.status, "value") else p.status,
         total_duration=p.total_duration,
+        result_count=getattr(p, "result_count", 0),
         project_id=p.project_id or "",
         created_by_user_id=p.created_by_user_id or "",
         config=p.config,