feat: 添加测试覆盖率并修复相关问题

refactor(redis_manager): 移除冗余的ConnectionError处理
refactor(event_handler): 优化Bot类型注解
refactor(factory): 移除未使用的GroupCardNoticeEvent

test: 添加全面的单元测试覆盖
- 添加test_import.py测试模块导入
- 添加test_debug.py测试插件加载调试
- 添加test_plugin_error.py测试错误处理
- 添加test_config_loader.py测试配置加载
- 添加test_redis_manager.py测试Redis管理
- 添加test_bot.py测试Bot功能
- 扩展test_models.py测试消息模型
- 添加test_plugin_manager_coverage.py测试插件管理
- 添加test_executor.py测试代码执行器
- 添加test_ws.py测试WebSocket
- 添加test_api.py测试API接口
- 添加test_core_managers.py测试核心管理模块

fix(plugin_manager): 修复插件加载日志变量问题

覆盖率已到达86%（忽略插件）

tests/test_redis_manager.py

@@ -0,0 +1,138 @@
+import pytest
+from unittest.mock import MagicMock, patch, AsyncMock
+from core.managers.redis_manager import RedisManager
+
+
+class TestRedisManager:
+    def test_singleton_pattern(self):
+        """测试单例模式。"""
+        instance1 = RedisManager()
+        instance2 = RedisManager()
+        assert instance1 is instance2
+
+    @pytest.mark.asyncio
+    async def test_initialize_success(self):
+        """测试 Redis 初始化成功。"""
+        # 重置单例
+        if hasattr(RedisManager, "_instance"):
+            del RedisManager._instance
+        # 确保类有 _instance 属性
+        if not hasattr(RedisManager, "_instance"):
+            RedisManager._instance = None
+        # 重置 Redis 连接
+        RedisManager._redis = None
+            
+        # 模拟全局配置
+        with patch('core.managers.redis_manager.config') as mock_config:
+            mock_config.redis.host = "localhost"
+            mock_config.redis.port = 6379
+            mock_config.redis.db = 0
+            mock_config.redis.password = "test_password"
+            
+            # 模拟 Redis 客户端
+            with patch('core.managers.redis_manager.redis') as mock_redis_module:
+                mock_redis = AsyncMock()
+                mock_redis.ping.return_value = True
+                mock_redis_module.Redis.return_value = mock_redis
+                
+                manager = RedisManager()
+                await manager.initialize()
+                
+                # 验证 Redis 连接
+                mock_redis_module.Redis.assert_called_once_with(
+                    host="localhost",
+                    port=6379,
+                    db=0,
+                    password="test_password",
+                    decode_responses=True
+                )
+                mock_redis.ping.assert_called_once()
+                assert manager._redis is mock_redis
+
+    @pytest.mark.asyncio
+    async def test_initialize_connection_error(self):
+        """测试 Redis 连接失败。"""
+        # 重置单例
+        if hasattr(RedisManager, "_instance"):
+            del RedisManager._instance
+        # 确保类有 _instance 属性
+        if not hasattr(RedisManager, "_instance"):
+            RedisManager._instance = None
+        # 重置 Redis 连接
+        RedisManager._redis = None
+            
+        # 模拟全局配置
+        with patch('core.managers.redis_manager.config') as mock_config:
+            mock_config.redis.host = "localhost"
+            mock_config.redis.port = 6379
+            mock_config.redis.db = 0
+            mock_config.redis.password = "test_password"
+            
+            # 模拟 Redis 连接错误
+            with patch('core.managers.redis_manager.redis') as mock_redis_module:
+                mock_redis_module.Redis.side_effect = Exception("Connection refused")
+                
+                manager = RedisManager()
+                await manager.initialize()
+                
+                # 验证 Redis 未初始化
+                assert manager._redis is None
+
+    def test_redis_property_uninitialized(self):
+        """测试 Redis 属性在未初始化时抛出异常。"""
+        # 重置单例
+        if hasattr(RedisManager, "_instance"):
+            del RedisManager._instance
+        # 确保类有 _instance 属性
+        if not hasattr(RedisManager, "_instance"):
+            RedisManager._instance = None
+        # 重置 Redis 连接
+        RedisManager._redis = None
+            
+        manager = RedisManager()
+        manager._redis = None
+        
+        with pytest.raises(ConnectionError, match="Redis 未初始化或连接失败，请先调用 initialize()"):
+            _ = manager.redis
+
+    @pytest.mark.asyncio
+    async def test_get_method(self):
+        """测试 get 方法。"""
+        # 重置单例
+        if hasattr(RedisManager, "_instance"):
+            del RedisManager._instance
+        # 确保类有 _instance 属性
+        if not hasattr(RedisManager, "_instance"):
+            RedisManager._instance = None
+        # 重置 Redis 连接
+        RedisManager._redis = None
+            
+        manager = RedisManager()
+        mock_redis = AsyncMock()
+        mock_redis.get.return_value = "test_value"
+        manager._redis = mock_redis
+        
+        result = await manager.get("test_key")
+        assert result == "test_value"
+        mock_redis.get.assert_called_once_with("test_key")
+
+    @pytest.mark.asyncio
+    async def test_set_method(self):
+        """测试 set 方法。"""
+        # 重置单例
+        if hasattr(RedisManager, "_instance"):
+            del RedisManager._instance
+        # 确保类有 _instance 属性
+        if not hasattr(RedisManager, "_instance"):
+            RedisManager._instance = None
+        # 重置 Redis 连接
+        RedisManager._redis = None
+            
+        manager = RedisManager()
+        mock_redis = AsyncMock()
+        mock_redis.set.return_value = True
+        manager._redis = mock_redis
+        
+        result = await manager.set("test_key", "test_value", ex=3600)
+        assert result is True
+        mock_redis.set.assert_called_once_with("test_key", "test_value", ex=3600)