fix(distribution): 修正分销后台入口地址并收口主站后台隐藏路径

- 新增前端 distributionAdmin 工具：优先 VITE_DISTRIBUTION_ADMIN_URL，
  本地开发回退 5190，生产按 distribution.<主站域名> 推导
- 替换主站后台「打开独立分销后台」按钮与开通凭证中硬编码的 :5190
- 分销后台复制凭证改用 window.location.origin，去掉硬编码 http
- Caddyfile 中 /manage-7x9k2p 仅主站域名放行，分站域名统一 404
- 构建/部署链路透传 VITE_DISTRIBUTION_ADMIN_URL 与 ADMIN_BASE_PATH

frontend/src/features/admin/views/AdminDistributionSitesView.vue

@@ -30,6 +30,10 @@ import { uploadAdminFile } from '@/shared/api/files'
 import AuthImage from '@/shared/components/business/AuthImage.vue'
 import { formatDateTime } from '@/shared/utils/time'
 import { readError } from '@/shared/utils/error'
+import {
+  distributionAdminBaseUrl,
+  distributionAdminLoginUrl,
+} from '@/shared/utils/distributionAdmin'
 
 const loading = ref(false)
 const sites = ref<DistributionSite[]>([])
@@ -423,13 +427,13 @@ async function handleOnboardSubmit() {
 
 function handleCopyInfo() {
   if (!onboardResult.value) return
-  const text = `分销站点：${onboardResult.value.site.site_name} (${onboardResult.value.site.site_code})\n分销域名：${onboardResult.value.site.domain}\n后台登录地址：http://${window.location.hostname}:5190/login\n管理员账号：${onboardResult.value.member.username}`
+  const text = `分销站点：${onboardResult.value.site.site_name} (${onboardResult.value.site.site_code})\n分销域名：${onboardResult.value.site.domain}\n后台登录地址：${distributionAdminLoginUrl()}\n管理员账号：${onboardResult.value.member.username}`
   navigator.clipboard?.writeText(text)
   ElMessage.success('已复制分销商开通凭证到剪贴板')
 }
 
 function openDistributionAdmin() {
-  window.open(`http://${window.location.hostname}:5190`, '_blank')
+  window.open(distributionAdminBaseUrl(), '_blank')
 }
 
 const syncingSiteId = ref<number | null>(null)
@@ -699,7 +703,7 @@ onMounted(() => {
             <el-tag type="success">{{ onboardResult.member.username }}</el-tag>
           </el-descriptions-item>
           <el-descriptions-item label="分销后台地址">
-            <code>http://{{ windowHost }}:5190/login</code>
+            <code>{{ distributionAdminLoginUrl() }}</code>
           </el-descriptions-item>
           <el-descriptions-item label="初始分成规则">
             四种模式均已按默认生效：收号 35% / 卖出 40% / 服务费 25%（本站自卖 75% +
@@ -925,16 +929,6 @@ onMounted(() => {
   </div>
 </template>
 
-<script lang="ts">
-export default {
-  data() {
-    return {
-      windowHost: typeof window !== 'undefined' ? window.location.hostname : 'localhost',
-    }
-  },
-}
-</script>
-
 <style scoped>
 .distribution-sites-view {
   padding: 20px;