feat(distribution): 分站发布群只使用自己的二维码池

主站单独维护分站码池，池空时不再借用主站或其他分站，并去掉已停用的固定二维码入口。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/router/adminRoutes.ts

@@ -222,6 +222,12 @@ export const adminRoutes: RouteRecordRaw[] = [
     component: () => import('@/features/admin/views/AdminDistributionSitesView.vue'),
     meta: adminMeta,
   },
+  {
+    path: adminPath('distribution/qrcode-pool'),
+    name: 'admin-distribution-qrcode-pool',
+    component: () => import('@/features/admin/views/AdminDistributionQrCodePoolView.vue'),
+    meta: adminMeta,
+  },
   {
     path: adminPath('distribution/rules'),
     name: 'admin-distribution-rules',