feat(timer): 新增定时器配置、日志和主机的后台管理界面

T10: TimerConfig CURD - task management with run_type/status editing,
     manual trigger button, task_name read-only, no add/delete
T11: TimerLog CURD - read-only log viewer with filters and color badges
T12: Host list enhanced - is_master column, setMaster button

extend/base/admin/view/system/host/_common.js

@@ -7,4 +7,5 @@ var init = {
     deleteUrl: 'system.host/delete',
     exportUrl: 'system.host/export',
     modifyUrl: 'system.host/modify',
+    set_master_url: 'system.host/setMaster',
 };