新增小程序后端代码，包括数据库、路由、服务层等。

小程序前后端打通，包括登录、注册、绑定设备、查询绑定信息，修改小朋友名称等功能。

mini-program/app/service/__init__.py

@@ -0,0 +1,12 @@
+from fastapi import Depends
+from sqlalchemy.orm import Session
+
+from app.db import get_db
+
+
+def get_db_session():
+    db = next(get_db())
+    try:
+        yield db
+    finally:
+        db.close()

mini-program/app/service/binding.py

@@ -0,0 +1,45 @@
+from collections.abc import Mapping
+from datetime import datetime
+from typing import Optional
+
+from app.dao.binding import BindingDAO
+
+
+class BindingService:
+    def __init__(self, db):
+        self.dao = BindingDAO(db)
+
+    def start_bind(self, user_id: int, device_id: str, child_id: int) -> tuple[str, datetime]:
+        bind_token = self.dao.start_bind(user_id, device_id, child_id)
+        return bind_token, datetime.utcnow()
+
+    def confirm_bind(self, bind_token: str, user_id: int) -> Mapping:
+        session = self.dao.get_session(bind_token, user_id)
+        if not session:
+            raise ValueError("Bind session not found")
+        if datetime.utcnow() > session["expires_at"]:
+            raise ValueError("Bind session expired")
+        if session["status"] != 1:
+            raise ValueError("Bind session already processed")
+
+        self.dao.confirm_bind(session["id"], session["device_id"], session["target_child_id"], user_id)
+        return {"device_id": session["device_id"], "child_id": session["target_child_id"]}
+
+    def get_binding(self, device_id: str, user_id: int) -> Optional[Mapping]:
+        return self.dao.get_by_device(device_id, user_id)
+
+    def get_current_binding(self, user_id: int) -> Optional[Mapping]:
+        return self.dao.get_current_by_user(user_id)
+
+    def direct_bind(self, device_id: str, child_id: int, user_id: int) -> Mapping:
+        self.dao.direct_bind(device_id, child_id, user_id)
+        return {"device_id": device_id, "child_id": child_id}
+
+    def unbind(self, device_id: str, user_id: int) -> bool:
+        return self.dao.unbind(device_id, user_id)
+
+    def list_history(self, device_id: str, limit: int = 20, cursor: datetime = None) -> tuple[list, bool]:
+        rows = self.dao.list_history(device_id, limit, cursor)
+        has_more = len(rows) > limit
+        rows = rows[:limit]
+        return rows, has_more

mini-program/app/service/child.py

@@ -0,0 +1,42 @@
+from collections.abc import Mapping
+from datetime import date
+from typing import Optional
+
+from app.dao.child import ChildDAO
+
+
+class ChildService:
+    def __init__(self, db):
+        self.dao = ChildDAO(db)
+
+    def create(
+        self,
+        user_id: int,
+        child_name: str,
+        child_gender: int = 2,
+        child_birthday: Optional[date] = None,
+    ) -> Mapping:
+        child_id = self.dao.create(user_id, child_name, child_gender, child_birthday)
+        return self.dao.get_by_id(child_id)
+
+    def list_children(self, user_id: int, limit: int = 20, cursor: int = None) -> tuple[list, bool]:
+        rows = self.dao.list_by_parent(user_id, limit, cursor)
+        has_more = len(rows) > limit
+        rows = rows[:limit]
+        return rows, has_more
+
+    def get(self, child_id: int) -> Optional[Mapping]:
+        return self.dao.get_by_id(child_id)
+
+    def update(
+        self,
+        child_id: int,
+        user_id: int,
+        child_name: Optional[str] = None,
+        child_gender: Optional[int] = None,
+        child_birthday: Optional[date] = None,
+    ) -> Mapping:
+        if not self.dao.has_access(child_id, user_id):
+            raise PermissionError("No access to this child")
+        self.dao.update(child_id, child_name, child_gender, child_birthday)
+        return self.dao.get_by_id(child_id)

mini-program/app/service/parent.py

@@ -0,0 +1,33 @@
+from collections.abc import Mapping
+from typing import Optional
+
+from app.dao.parent import ParentDAO
+from app.service import get_db_session
+
+
+class ParentService:
+    def __init__(self, db):
+        self.dao = ParentDAO(db)
+
+    def create(
+        self,
+        openid: str,
+        unionid: Optional[str] = None,
+        nickname: Optional[str] = None,
+        avatar_url: Optional[str] = None,
+    ) -> Mapping:
+        user_id = self.dao.upsert(openid, unionid, nickname, avatar_url)
+        return self.dao.get_by_id(user_id)
+
+    def get(self, user_id: int) -> Optional[Mapping]:
+        return self.dao.get_by_id(user_id)
+
+    def update(
+        self,
+        user_id: int,
+        nickname: Optional[str] = None,
+        avatar_url: Optional[str] = None,
+        phone: Optional[str] = None,
+    ) -> Mapping:
+        self.dao.update(user_id, nickname, avatar_url, phone)
+        return self.dao.get_by_id(user_id)