feat(push-management): 在服务门户栏添加「厂商凭据配置」快速跳转

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

tenant-platform/src/views/push/PushManagementView.vue

@@ -5,6 +5,7 @@
       <el-select :model-value="appKey" placeholder="选择应用" style="width:220px" @change="switchApp">
         <el-option v-for="a in portalApps" :key="a.appKey" :label="a.name" :value="a.appKey" />
       </el-select>
+      <el-button v-if="appKey" link type="primary" @click="$router.push(`/apps/${appKey}/push-config`)">厂商凭据配置 →</el-button>
     </div>
     <el-page-header v-else @back="$router.back()" content="推送管理" style="margin-bottom:24px" />
     <el-empty v-if="isServicesPortal && !appKey" description="请选择一个应用" style="margin-top:80px" />