fix(timer): 自动记录执行日志并捕获结果

Add execute() wrapper in TimerControllerBase that wraps do() with logStart/logEnd, captures return value to result field. Change site URL routing from /do to /execute with task_name injection. Add result field to system_timer_log scheme.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

app/admin/scheme/SystemTimerLog.php

@@ -50,6 +50,10 @@ class SystemTimerLog extends BaseScheme
     #[Component(type: 'textarea', options: [])]
     public $error_message;
 
+    #[Field(type: 'text', nullable: true, comment: '执行结果(任务返回值)')]
+    #[Component(type: 'textarea', options: [])]
+    public $result;
+
     #[Field(type: 'int', length: 11, default: '0', comment: '并发分片ID')]
     #[Component(type: 'text', options: [])]
     public $concurrency_id;