refactor(scheduler): 将统一调度器移动至插件系统API

将统一调度器模块从 `src/schedule/` 目录重构至 `src/plugin_system/apis/` 目录下。

这次调整旨在将调度器明确地定位为插件系统的核心API之一，从而改善代码的组织结构和架构清晰度。所有引用该模块的内部导入路径均已同步更新。

src/plugins/built_in/affinity_flow_chatter/proactive/proactive_thinking_scheduler.py

@@ -9,7 +9,7 @@ from datetime import datetime, timedelta
 from typing import Any
 
 from src.common.logger import get_logger
-from src.schedule.unified_scheduler import TriggerType, unified_scheduler
+from src.plugin_system.apis.unified_scheduler import TriggerType, unified_scheduler
 
 logger = get_logger("proactive_thinking_scheduler")
 

src/plugins/built_in/system_management/plugin.py

@@ -23,7 +23,7 @@ from src.plugin_system.base.component_types import (
 from src.plugin_system.base.config_types import ConfigField
 from src.plugin_system.base.plus_command import PlusCommand
 from src.plugin_system.utils.permission_decorators import require_permission
-from src.schedule.unified_scheduler import TriggerType, unified_scheduler
+from src.plugin_system.apis.unified_scheduler import TriggerType, unified_scheduler
 
 logger = get_logger("SystemManagement")