修复：增强 SMTP 连通性测试容错，加入 10 秒超时限制避免端口不通导致页面死锁，并捕获 Throwable 防止致命异常

app/Http/Controllers/Admin/SmtpController.php

@@ -77,7 +77,7 @@ class SmtpController extends Controller
             });
 
             return redirect()->route('admin.smtp.edit')->with('success', "测试邮件已成功发送至 {$testEmail}，请注意查收。");
-        } catch (\Exception $e) {
+        } catch (\Throwable $e) {
             return redirect()->route('admin.smtp.edit')->with('error', "测试发出失败，原因：" . $e->getMessage());
         }
     }

app/Providers/AppServiceProvider.php

@@ -36,7 +36,7 @@ class AppServiceProvider extends ServiceProvider
                         'encryption' => $smtpConfig->get('smtp_encryption', 'ssl'),
                         'username' => $smtpConfig->get('smtp_username'),
                         'password' => $smtpConfig->get('smtp_password'),
-                        'timeout' => null,
+                        'timeout'  => 10,
                         'local_domain' => env('MAIL_EHLO_DOMAIN'),
                     ]);