refactor: 积分系统拆分为独立 erp-points crate

- 新建 erp-points crate（8 Entity + account/product service + handler）
- 商品 CRUD 和账户管理完整实现，订单/签到/规则端点暂返回 501
- 注册到 workspace + erp-server 路由 /api/v1/points/*
- API 路径不变，前端无需修改

crates/erp-points/src/entity/points_order.rs

@@ -33,19 +33,6 @@ pub struct Model {
 }
 
 #[derive(Copy, Clone, Debug, EnumIter, DeriveRelation)]
-pub enum Relation {
-    #[sea_orm(
-        belongs_to = "super::patient::Entity",
-        from = "Column::PatientId",
-        to = "super::patient::Column::Id"
-    )]
-    Patient,
-}
-
-impl Related<super::patient::Entity> for Entity {
-    fn to() -> RelationDef {
-        Relation::Patient.def()
-    }
-}
+pub enum Relation {}
 
 impl ActiveModelBehavior for ActiveModel {}