feat: add batch host migration and expiry offset

src/views/user-vm/UserVmDetail.vue

@@ -889,6 +889,10 @@
             </el-form-item>
           </el-col>
         </el-row>
+        <el-form-item label="到期顺延">
+          <el-input-number v-model="migrateForm.expire_offset_days" :min="0" :step="1" :precision="0" controls-position="right" style="width:100%" />
+          <div style="font-size:12px;color:#909399">迁移完成后，用户商品到期时间向后顺延；0 表示不调整</div>
+        </el-form-item>
       </el-form>
       <template #footer>
         <el-button @click="migrateVisible = false">取消</el-button>
@@ -2049,10 +2053,10 @@ const migrateOptionsLoading = ref(false)
 const migrateMode = ref('host')
 const migrateHostOptions = ref([])
 const migrateGroupOptions = ref([])
-const migrateForm = reactive({ target_host_id: null, target_host_group_id: null, ipv4_num: 0, ipv6_num: 0 })
+const migrateForm = reactive({ target_host_id: null, target_host_group_id: null, ipv4_num: 0, ipv6_num: 0, expire_offset_days: 0 })
 
 const openMigrateVm = async () => {
-  Object.assign(migrateForm, { target_host_id: null, target_host_group_id: null, ipv4_num: 0, ipv6_num: 0 })
+  Object.assign(migrateForm, { target_host_id: null, target_host_group_id: null, ipv4_num: 0, ipv6_num: 0, expire_offset_days: 0 })
   migrateMode.value = 'host'
   migrateVisible.value = true
   migrateOptionsLoading.value = true
@@ -2097,6 +2101,7 @@ const submitMigrateVm = async () => {
     else payload.target_host_group_id = migrateForm.target_host_group_id
     if (migrateForm.ipv4_num) payload.ipv4_num = migrateForm.ipv4_num
     if (migrateForm.ipv6_num) payload.ipv6_num = migrateForm.ipv6_num
+    if (migrateForm.expire_offset_days > 0) payload.expire_offset_days = migrateForm.expire_offset_days
     const res = await migrateUserVm(payload)
     if (res?.data?.code === 200) {
       const migrationData = res.data.data || {}