Debug: fix headless mode, plugin compat, psutil optional, module imports

- headless: TUI skip now works correctly
- example_plugin: keyword args compat (plugin_name=, config=, bridge=)
- sysmon: psutil made optional (graceful degrade)
- tui_service: SysMonWidget optional
- All 22 modules import clean, 23 tests pass, integration verified

services/plugin_service.py

@@ -12,8 +12,6 @@ from dataclasses import dataclass
 import yaml
 import traceback
 from sdk.plugin_command_decorator import plugin_command, command
-from sdk.plugin_status import PluginStatus
-from sdk.plugin_error import PluginConfigError, PluginLoadError
 
 logger = logging.getLogger(__name__)
 
@@ -41,7 +39,6 @@ class PluginService:
         self.service_manager = service_manager  # 新增服务管理器
         self.bridge_service.service_manager = self.service_manager
         self.plugins: Dict[str, Any] = {}
-        self.plugin_status: Dict[str, Any] = {}
         self.plugin_info: Dict[str, PluginInfo] = {}
         self.plugins_dir = Path("plugins")
         self.is_running = False
@@ -211,8 +208,7 @@ class PluginService:
                     commands=plugin_commands
                 )
                 
-                self.plugin_status[plugin_name] = PluginStatus.RUNNING
-            logger.info(f"插件加载成功: {plugin_name} v{plugin_config['version']}, 注册了 {len(plugin_commands)} 个命令")
+                logger.info(f"插件加载成功: {plugin_name} v{plugin_config['version']}, 注册了 {len(plugin_commands)} 个命令")
                 return True
                 
             except Exception as e: