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）

test_plugin_error.py

@@ -0,0 +1,55 @@
+import sys
+import os
+from unittest.mock import patch, MagicMock
+
+# 添加项目根目录到Python路径
+sys.path.insert(0, os.path.dirname(os.path.abspath(__file__)))
+
+# 导入插件管理器
+from core.managers.plugin_manager import PluginManager
+
+# 创建测试用例
+def test_plugin_error_handling():
+    # 创建命令管理器模拟
+    mock_command_manager = MagicMock()
+    mock_command_manager.plugins = {}
+    
+    # 创建插件管理器
+    pm = PluginManager(mock_command_manager)
+    
+    # 模拟导入错误
+    def import_side_effect(name, *args, **kwargs):
+        if name == "plugins.bad_plugin":
+            raise Exception("Load error")
+        mock_module = MagicMock()
+        mock_module.__plugin_meta__ = {"name": "Test Plugin"}
+        return mock_module
+    
+    # 打桩
+    with patch("pkgutil.iter_modules") as mock_iter, \
+         patch("importlib.import_module", side_effect=import_side_effect), \
+         patch("os.path.exists", return_value=True), \
+         patch("core.managers.plugin_manager.logger") as mock_logger:
+        
+        mock_iter.return_value = [(None, "bad_plugin", False)]
+        
+        # 执行加载
+        pm.load_all_plugins()
+        
+        # 验证
+        assert "plugins.bad_plugin" not in pm.loaded_plugins
+        print(f"DEBUG: mock_logger.exception.called: {mock_logger.exception.called}")
+        print(f"DEBUG: mock_logger.error.called: {mock_logger.error.called}")
+        print(f"DEBUG: mock_logger method calls: {mock_logger.method_calls}")
+        
+        # 检查是否调用了日志
+        if mock_logger.exception.called:
+            print("SUCCESS: logger.exception was called")
+        elif mock_logger.error.called:
+            print("SUCCESS: logger.error was called")
+        else:
+            print("ERROR: No logger method was called!")
+
+# 运行测试
+if __name__ == "__main__":
+    test_plugin_error_handling()