refactor(todo): 移除 due_at 字段，改用 order 字段管理象限内顺序

backend/src/v1/todo/schemas.py

@@ -5,14 +5,16 @@ from uuid import UUID
 
 from pydantic import BaseModel, ConfigDict, Field
 
+from schemas.todo import TodoOrder
+
 
 class TodoCreate(BaseModel):
     model_config: ClassVar[ConfigDict] = ConfigDict(extra="forbid")
 
     title: str = Field(..., min_length=1, max_length=255)
     description: str | None = Field(None, max_length=1000)
-    due_at: datetime | None = None
     priority: int = Field(1, ge=1, le=4)
+    order: TodoOrder | None = None
     schedule_item_ids: list[UUID] = Field(default_factory=list)
 
 
@@ -21,8 +23,8 @@ class TodoUpdate(BaseModel):
 
     title: str | None = Field(None, min_length=1, max_length=255)
     description: str | None = Field(None, max_length=1000)
-    due_at: datetime | None = None
     priority: int | None = Field(None, ge=1, le=4)
+    order: TodoOrder | None = None
     status: Literal["pending", "done", "canceled"] | None = None
     schedule_item_ids: list[UUID] | None = None
 
@@ -43,8 +45,8 @@ class TodoResponse(BaseModel):
     owner_id: UUID
     title: str
     description: str | None
-    due_at: datetime | None
     priority: int
+    order: TodoOrder
     status: str
     completed_at: datetime | None
     created_at: datetime
@@ -52,6 +54,20 @@ class TodoResponse(BaseModel):
     schedule_items: list[ScheduleItemBasic] = Field(default_factory=list)
 
 
+class TodoReorderItem(BaseModel):
+    model_config: ClassVar[ConfigDict] = ConfigDict(extra="forbid")
+
+    id: UUID
+    priority: int = Field(..., ge=1, le=4)
+    order: TodoOrder
+
+
+class TodoReorderRequest(BaseModel):
+    model_config: ClassVar[ConfigDict] = ConfigDict(extra="forbid")
+
+    items: list[TodoReorderItem] = Field(..., min_length=1)
+
+
 class TodoComplete(BaseModel):
     model_config: ClassVar[ConfigDict] = ConfigDict(extra="forbid")