feature: 数据库连接与SQL集中管理，提高代码可读性

db/sign_in_redis.py

@@ -0,0 +1,77 @@
+# -*- coding: utf-8 -*-
+from datetime import datetime
+from typing import Dict, Optional
+
+from db.connection import DBConnectionManager
+
+
+class SignInRedisDB:
+    """签到系统Redis相关操作"""
+    
+    def __init__(self, db_manager: DBConnectionManager):
+        self.db_manager = db_manager
+        self.prefix = "group:sign_in:"
+    
+    def get_redis_connection(self):
+        """获取Redis连接"""
+        return self.db_manager.get_redis_connection()
+    
+    def load_signin_count(self) -> Dict[str, int]:
+        """加载签到人数数据"""
+        signin_count = {}
+        with self.get_redis_connection() as redis_client:
+            keys = redis_client.keys(f'{self.prefix}*')
+            for key in keys:
+                if isinstance(key, bytes):
+                    key = key.decode('utf-8')
+                if key == f'{self.prefix}last_reset_date':
+                    continue
+                group_id = key.replace(self.prefix, '')
+                count = redis_client.get(key)
+                if count is not None:
+                    if isinstance(count, bytes):
+                        count = count.decode('utf-8')
+                    signin_count[group_id] = int(count)
+        return signin_count
+    
+    def save_signin_count(self, group_id: str, count: int) -> bool:
+        """保存签到人数"""
+        try:
+            with self.get_redis_connection() as redis_client:
+                redis_client.set(f'{self.prefix}{group_id}', count)
+            return True
+        except Exception:
+            return False
+    
+    def get_last_reset_date(self) -> Optional[datetime.date]:
+        """获取最后重置日期"""
+        with self.get_redis_connection() as redis_client:
+            date_str = redis_client.get(f'{self.prefix}last_reset_date')
+            if date_str:
+                if isinstance(date_str, bytes):
+                    date_str = date_str.decode('utf-8')
+                return datetime.strptime(date_str, '%Y-%m-%d').date()
+        return None
+    
+    def save_last_reset_date(self, date: datetime.date) -> bool:
+        """保存最后重置日期"""
+        try:
+            with self.get_redis_connection() as redis_client:
+                redis_client.set(f'{self.prefix}last_reset_date', date.strftime('%Y-%m-%d'))
+            return True
+        except Exception:
+            return False
+    
+    def reset_daily_counts(self) -> bool:
+        """重置每日签到计数"""
+        try:
+            with self.get_redis_connection() as redis_client:
+                keys = redis_client.keys(f'{self.prefix}*')
+                for key in keys:
+                    if isinstance(key, bytes):
+                        key = key.decode('utf-8')
+                    if key != f'{self.prefix}last_reset_date':
+                        redis_client.delete(key)
+            return True
+        except Exception:
+            return False