fix(admin): 平台推送地址优先回显已配置的公网域名

- 引入 resolveDouyinMashidaPublicOrigin 从已配置的 claimLinkBase/certLink 提取公网域名
- 更新后台面板 message_url 展示逻辑，即使从 localhost 访问也清晰呈现已配置的公网推送地址
- 向平台订阅推送时使用已解析的公网域名，避免错误推送 localhost
- 补充前端单元测试并通过全量构建校验

apps/frontend/tests/douyin-mashida.test.ts

@@ -8,6 +8,7 @@ import {
   buildDouyinMashidaMessageUrl,
   describeMissingConfigFields,
   isLocalDevBaseUrl,
+  resolveDouyinMashidaPublicOrigin,
 } from '../src/utils/douyin-mashida.ts'
 
 /** 固定顺序：接入开关 / 商户uid / 用户秘钥 / 兑换链接 */
@@ -126,3 +127,19 @@ test('发消息模板提示：没有 {link} 就等于没给买家链接', () =>
   assert.equal(describeMessageTemplateWarning(''), '')
   assert.match(describeMessageTemplateWarning('您的订单已发货'), /\{link\}/)
 })
+
+test('resolveDouyinMashidaPublicOrigin：从已配置的 claimLinkBase 或 certLink 提取公网 origin', () => {
+  assert.equal(
+    resolveDouyinMashidaPublicOrigin('https://nonsecretly-posttracheal-amado.ngrok-free.dev/h5'),
+    'https://nonsecretly-posttracheal-amado.ngrok-free.dev',
+  )
+  assert.equal(
+    resolveDouyinMashidaPublicOrigin('', 'https://my-domain.com/h5'),
+    'https://my-domain.com',
+  )
+  assert.equal(
+    resolveDouyinMashidaPublicOrigin('', '', 'http://localhost:5173'),
+    'http://localhost:5173',
+  )
+})
+