feat(core): 优化扩展启动逻辑并修复类型提示问题

- 修改 CoreService 启动逻辑，将 system 扩展实例存入 bootedExtensionMap
- 修复 functions.php 中 running_in_console 函数返回值缺失问题
- 统一多个服务类中的可空参数类型声明
- 新增 HelloCron 定时任务并注册到扩展中
- 优化 GatheringCrontabEventHook 中定时任务初始化逻辑
- 增强 Cron 注解解析与任务执行检查机制

src/Service/CoreService.php

@@ -93,7 +93,8 @@ class CoreService extends Service
     {
         $autoloadService = $this->app->make(AutoloadService::class);
         $autoloadService->load(self::$extensionComposerMap);
-        $this->app->get('extension.system')->boot();
+        $this->bootedExtensionMap['system'] = $this->app->get('extension.system');
+        $this->bootedExtensionMap['system']->boot();
         foreach (self::$extensionComposerMap as $moduleName => $_) {
             $extension = $autoloadService->getExtension($moduleName);
             if (!$extension->available() || $extension->isBooted()) {

src/functions.php

@@ -200,5 +200,5 @@ function extension_composer_info(string $extensionID): array
  */
 function running_in_console(): bool
 {
-    php_sapi_name() === 'cli' || php_sapi_name() === 'phpdbg';
+    return php_sapi_name() === 'cli' || php_sapi_name() === 'phpdbg';
 }