feat(init): 添加完整的认证和业务路由模块

- 实现微信登录、手机号绑定、token验证和登出功能
- 添加打卡系统，支持正常、迟到、请假等状态记录
- 集成课程投票功能，支持多课程选择和评分评论
- 开发反馈系统，支持图文反馈提交和管理员处理
- 构建首页页面模块，动态展示学习资源和个人信息
- 设计计划管理系统，支持周/月/年计划制定和跟踪
- 实现小组计划统计和历史记录查询功能
- 完善用户认证会话管理和数据库交互逻辑

wechat.py

@@ -0,0 +1,55 @@
+import httpx
+
+from . import config
+
+
+class WeChatError(Exception):
+    pass
+
+
+def code_to_openid(code):
+    resp = httpx.get(
+        "https://api.weixin.qq.com/sns/jscode2session",
+        params={
+            "appid": config.WECHAT_APPID,
+            "secret": config.WECHAT_SECRET,
+            "js_code": code,
+            "grant_type": "authorization_code",
+        },
+        timeout=10,
+    )
+    data = resp.json()
+    if data.get("errcode") or "openid" not in data:
+        raise WeChatError(data.get("errmsg", "无效的登录 code"))
+    return data["openid"]
+
+
+def _get_access_token():
+    resp = httpx.get(
+        "https://api.weixin.qq.com/cgi-bin/token",
+        params={
+            "grant_type": "client_credential",
+            "appid": config.WECHAT_APPID,
+            "secret": config.WECHAT_SECRET,
+        },
+        timeout=10,
+    )
+    data = resp.json()
+    if not data.get("access_token"):
+        raise WeChatError(data.get("errmsg", "获取微信 access_token 失败"))
+    return data["access_token"]
+
+
+def get_phone_number(phone_code):
+    access_token = _get_access_token()
+    resp = httpx.post(
+        "https://api.weixin.qq.com/wxa/business/getuserphonenumber",
+        params={"access_token": access_token},
+        json={"code": phone_code},
+        timeout=10,
+    )
+    data = resp.json()
+    if data.get("errcode") != 0:
+        raise WeChatError(data.get("errmsg", "获取手机号失败"))
+    phone_info = data.get("phone_info") or {}
+    return phone_info.get("purePhoneNumber") or phone_info.get("phoneNumber")