feat：完善项目信息

app/api/enterprise/model/bill_instance.go

@@ -0,0 +1,11 @@
+package model
+
+import "SciencesServer/app/common/model"
+
+type BillInstance struct {
+	*model.BillInstance
+}
+
+func NewBillInstance() *BillInstance {
+	return &BillInstance{model.NewBillInstance()}
+}