Title: Implement minimal core framework with PL injection and update build config

Key features implemented:
- Updated package metadata and dependencies in PKG-INFO, setup files
- Added main.py entry point for backward compatibility with README launch method
- Enhanced CLI with config options, system info command, and proper signal handling
- Implemented minimal PluginManager loading only plugin-loader core plugin
- Refactored PluginLoader to follow minimal core design, removed sandbox/isolation complexity
- Updated auto-dependency plugin with safer PL injection mechanism and disabled pl_injection
- Removed legacy plugin files (firewall, frp_proxy, ftp_server, multi_lang_deploy, ops_toolbox, security_gateway) as functionality moved to core plugin system
- Improved gitignore with comprehensive ignore patterns

The changes implement a minimal core framework design where only the plugin-loader is directly loaded by the core, with all other plugins managed through the PL injection mechanism, significantly simplifying the architecture.

tests/test_plugin_manager.py

@@ -0,0 +1,53 @@
+"""插件管理器单元测试"""
+import pytest
+from oss.plugin.manager import PluginManager
+
+
+class TestPluginManager:
+    """测试插件管理器核心功能"""
+
+    def test_manager_initialization(self):
+        """测试管理器初始化"""
+        manager = PluginManager()
+        assert manager.plugin_loader is None
+        assert manager.loader is not None
+
+    def test_manager_load(self):
+        """测试管理器加载 plugin-loader"""
+        manager = PluginManager()
+        manager.load()
+        
+        assert manager.plugin_loader is not None
+        assert hasattr(manager.plugin_loader, "init")
+        assert hasattr(manager.plugin_loader, "start")
+        assert hasattr(manager.plugin_loader, "stop")
+
+    def test_manager_start_without_load(self):
+        """测试未加载时启动（应安全处理）"""
+        manager = PluginManager()
+        # 不应抛出异常
+        manager.start()
+
+    def test_manager_stop_without_load(self):
+        """测试未加载时停止（应安全处理）"""
+        manager = PluginManager()
+        # 不应抛出异常
+        manager.stop()
+
+    def test_manager_lifecycle(self):
+        """测试完整生命周期"""
+        manager = PluginManager()
+        
+        # 加载
+        manager.load()
+        assert manager.plugin_loader is not None
+        
+        # 启动（会初始化所有插件）
+        # 注意：实际启动需要完整环境，这里只测试方法存在
+        assert callable(manager.plugin_loader.init)
+        assert callable(manager.plugin_loader.start)
+        assert callable(manager.plugin_loader.stop)
+
+
+if __name__ == "__main__":
+    pytest.main([__file__, "-v"])