refactor: 统一 sqlmodel_ext 用法至官方推荐模式

- 替换 Field(max_length=X) 为 StrX/TextX 类型别名（21 个 sqlmodels 文件）
- 替换 get + 404 检查为 get_exist_one()（17 个路由文件，约 50 处）
- 替换 save + session.refresh 为 save(load=...)
- 替换 session.add + commit 为 save()（dav/provider.py）
- 更新所有依赖至最新版本

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

sqlmodels/order.py

@@ -1,58 +1,122 @@
+from decimal import Decimal
 from enum import StrEnum
 from typing import TYPE_CHECKING
 from uuid import UUID
 
+from sqlalchemy import Numeric
 from sqlmodel import Field, Relationship
 
-from sqlmodel_ext import SQLModelBase, TableBaseMixin
+from sqlmodel_ext import SQLModelBase, TableBaseMixin, Str255
 
 if TYPE_CHECKING:
+    from .product import Product
     from .user import User
 
 
 class OrderStatus(StrEnum):
     """订单状态枚举"""
+
     PENDING = "pending"
     """待支付"""
+
     COMPLETED = "completed"
     """已完成"""
+
     CANCELLED = "cancelled"
     """已取消"""
 
 
 class OrderType(StrEnum):
     """订单类型枚举"""
-    # [TODO] 补充具体订单类型
-    pass
 
+    STORAGE_PACK = "storage_pack"
+    """容量包"""
+
+    GROUP_TIME = "group_time"
+    """用户组时长"""
+
+    SCORE = "score"
+    """积分充值"""
+
+
+# ==================== DTO 模型 ====================
+
+class CreateOrderRequest(SQLModelBase):
+    """创建订单请求 DTO"""
+
+    product_id: UUID
+    """商品UUID"""
+
+    num: int = Field(default=1, ge=1)
+    """购买数量"""
+
+    method: str
+    """支付方式"""
+
+
+class OrderResponse(SQLModelBase):
+    """订单响应 DTO"""
+
+    id: int
+    """订单ID"""
+
+    order_no: str
+    """订单号"""
+
+    type: OrderType
+    """订单类型"""
+
+    method: str | None = None
+    """支付方式"""
+
+    product_id: UUID | None = None
+    """商品UUID"""
+
+    num: int
+    """购买数量"""
+
+    name: str
+    """商品名称"""
+
+    price: float
+    """订单价格（元）"""
+
+    status: OrderStatus
+    """订单状态"""
+
+    user_id: UUID
+    """所属用户UUID"""
+
+
+# ==================== 数据库模型 ====================
 
 class Order(SQLModelBase, TableBaseMixin):
     """订单模型"""
 
-    order_no: str = Field(max_length=255, unique=True, index=True)
+    order_no: Str255 = Field(unique=True, index=True)
     """订单号，唯一"""
 
-    type: int = Field(default=0, sa_column_kwargs={"server_default": "0"})
-    """订单类型 [TODO] 待定义枚举"""
+    type: OrderType
+    """订单类型"""
 
-    method: str | None = Field(default=None, max_length=255)
+    method: Str255 | None = None
     """支付方式"""
 
-    product_id: int | None = Field(default=None)
-    """商品ID"""
+    product_id: UUID | None = Field(default=None, foreign_key="product.id", ondelete="SET NULL")
+    """关联商品UUID"""
 
     num: int = Field(default=1, sa_column_kwargs={"server_default": "1"})
     """购买数量"""
 
-    name: str = Field(max_length=255)
+    name: Str255
     """商品名称"""
 
-    price: int = Field(default=0, sa_column_kwargs={"server_default": "0"})
-    """订单价格（分）"""
+    price: Decimal = Field(sa_type=Numeric(12, 2), default=Decimal("0.00"))
+    """订单价格（元）"""
 
     status: OrderStatus = Field(default=OrderStatus.PENDING)
     """订单状态"""
-    
+
     # 外键
     user_id: UUID = Field(
         foreign_key="user.id",
@@ -60,6 +124,22 @@ class Order(SQLModelBase, TableBaseMixin):
         ondelete="CASCADE"
     )
     """所属用户UUID"""
-    
+
     # 关系
-    user: "User" = Relationship(back_populates="orders")
+    user: "User" = Relationship(back_populates="orders")
+    product: "Product" = Relationship(back_populates="orders")
+
+    def to_response(self) -> OrderResponse:
+        """转换为响应 DTO"""
+        return OrderResponse(
+            id=self.id,
+            order_no=self.order_no,
+            type=self.type,
+            method=self.method,
+            product_id=self.product_id,
+            num=self.num,
+            name=self.name,
+            price=float(self.price),
+            status=self.status,
+            user_id=self.user_id,
+        )