fix(api): 修复墙检测任务超时占用与状态展示

为超过 5 分钟未领取或未上报的 pending/checking
任务自动标记失败，避免长期占用 active 状态并阻塞新检测

同时区分前端“等待节点领取”和“检测中”展示，
补充跳过原因提示，并更新相关测试与文档

app/Console/Commands/SyncServerGfwChecks.php

@@ -19,11 +19,12 @@ class SyncServerGfwChecks extends Command
         );
 
         $this->info(sprintf(
-            'Server GFW checks synced: total=%d started=%d skipped=%d active=%d',
+            'Server GFW checks synced: total=%d started=%d skipped=%d active=%d expired=%d',
             $result['total'],
             count($result['started']),
             count($result['skipped']),
-            $result['active']
+            $result['active'],
+            $result['expired'] ?? 0
         ));
 
         return self::SUCCESS;