feat: 套餐有效期支持日/周/月单位，订阅履约改用兑换码流程，UI层次感优化

- Prisma: SubscriptionPlan 新增 validityUnit 字段 (day/week/month)
- 新增 subscription-utils.ts 计算实际天数及格式化显示
- Sub2API client createAndRedeem 支持 subscription 类型 (group_id, validity_days)
- 订阅履约从 assignSubscription 改为 createAndRedeem，在 Sub2API 留痕
- 订单创建动态计算天数（月单位按自然月差值）
- 管理后台表单支持有效期数值+单位下拉
- 前端 ChannelCard 渠道卡片视觉层次优化（模型标签渐变、倍率突出、闪电图标）
- 按量付费 banner 改为渐变背景+底部倍率说明标签
- 帮助/客服信息区块添加到充值、订阅、支付全流程页面
- 移除系统配置独立页面入口，subscriptions API 返回用户信息

src/lib/order/service.ts

@@ -6,7 +6,8 @@ import { getMethodDailyLimit } from './limits';
 import { getMethodFeeRate, calculatePayAmount } from './fee';
 import { initPaymentProviders, paymentRegistry } from '@/lib/payment';
 import type { PaymentType, PaymentNotification } from '@/lib/payment';
-import { getUser, createAndRedeem, subtractBalance, addBalance, getGroup, assignSubscription } from '@/lib/sub2api/client';
+import { getUser, createAndRedeem, subtractBalance, addBalance, getGroup } from '@/lib/sub2api/client';
+import { computeValidityDays, type ValidityUnit } from '@/lib/subscription-utils';
 import { Prisma } from '@prisma/client';
 import { deriveOrderState, isRefundStatus } from './status';
 import { pickLocaleText, type Locale } from '@/lib/locale';
@@ -56,7 +57,7 @@ export async function createOrder(input: CreateOrderInput): Promise<CreateOrderR
   const orderType = input.orderType ?? 'balance';
 
   // ── 订阅订单前置校验 ──
-  let subscriptionPlan: { id: string; groupId: number; price: Prisma.Decimal; validityDays: number; name: string } | null = null;
+  let subscriptionPlan: { id: string; groupId: number; price: Prisma.Decimal; validityDays: number; validityUnit: string; name: string } | null = null;
   if (orderType === 'subscription') {
     if (!input.planId) {
       throw new OrderError('INVALID_INPUT', message(locale, '订阅订单必须指定套餐', 'Subscription order requires a plan'), 400);
@@ -180,7 +181,9 @@ export async function createOrder(input: CreateOrderInput): Promise<CreateOrderR
         orderType,
         planId: subscriptionPlan?.id ?? null,
         subscriptionGroupId: subscriptionPlan?.groupId ?? null,
-        subscriptionDays: subscriptionPlan?.validityDays ?? null,
+        subscriptionDays: subscriptionPlan
+          ? computeValidityDays(subscriptionPlan.validityDays, subscriptionPlan.validityUnit as ValidityUnit)
+          : null,
       },
     });
 
@@ -598,12 +601,16 @@ export async function executeSubscriptionFulfillment(orderId: string): Promise<v
       throw new Error(`Subscription group ${order.subscriptionGroupId} no longer exists or inactive`);
     }
 
-    await assignSubscription(
+    await createAndRedeem(
+      order.rechargeCode,
+      Number(order.amount),
       order.userId,
-      order.subscriptionGroupId,
-      order.subscriptionDays,
       `sub2apipay subscription order:${orderId}`,
-      `sub2apipay:subscription:${order.rechargeCode}`,
+      {
+        type: 'subscription',
+        groupId: order.subscriptionGroupId,
+        validityDays: order.subscriptionDays,
+      },
     );
 
     await prisma.order.updateMany({

src/lib/sub2api/client.ts

@@ -60,15 +60,20 @@ export async function createAndRedeem(
   value: number,
   userId: number,
   notes: string,
+  options?: { type?: 'balance' | 'subscription'; groupId?: number; validityDays?: number },
 ): Promise<Sub2ApiRedeemCode> {
   const env = getEnv();
   const url = `${env.SUB2API_BASE_URL}/api/v1/admin/redeem-codes/create-and-redeem`;
   const body = JSON.stringify({
     code,
-    type: 'balance',
+    type: options?.type ?? 'balance',
     value,
     user_id: userId,
     notes,
+    ...(options?.type === 'subscription' && {
+      group_id: options.groupId,
+      validity_days: options.validityDays,
+    }),
   });
 
   let lastError: unknown;

src/lib/subscription-utils.ts

@@ -0,0 +1,90 @@
+export type ValidityUnit = 'day' | 'week' | 'month';
+
+/**
+ * 根据数值和单位计算实际有效天数。
+ * - day: 直接返回
+ * - week: value * 7
+ * - month: 从 fromDate 到 value 个月后同一天的天数差
+ */
+export function computeValidityDays(value: number, unit: ValidityUnit, fromDate?: Date): number {
+  if (unit === 'day') return value;
+  if (unit === 'week') return value * 7;
+
+  // month: 计算到 value 个月后同一天的天数差
+  const from = fromDate ?? new Date();
+  const target = new Date(from);
+  target.setMonth(target.getMonth() + value);
+  return Math.round((target.getTime() - from.getTime()) / (1000 * 60 * 60 * 24));
+}
+
+/**
+ * 智能格式化有效期显示文本。
+ * - unit=month, value=1 → 包月 / Monthly
+ * - unit=month, value=3 → 包3月 / 3 Months
+ * - unit=week, value=2 → 包2周 / 2 Weeks
+ * - unit=day, value=30 → 包月 / Monthly (特殊处理)
+ * - unit=day, value=90 → 包90天 / 90 Days
+ */
+export function formatValidityLabel(
+  value: number,
+  unit: ValidityUnit,
+  locale: 'zh' | 'en',
+): string {
+  if (unit === 'month') {
+    if (value === 1) return locale === 'zh' ? '包月' : 'Monthly';
+    return locale === 'zh' ? `包${value}月` : `${value} Months`;
+  }
+  if (unit === 'week') {
+    if (value === 1) return locale === 'zh' ? '包周' : 'Weekly';
+    return locale === 'zh' ? `包${value}周` : `${value} Weeks`;
+  }
+  // day
+  if (value === 30) return locale === 'zh' ? '包月' : 'Monthly';
+  return locale === 'zh' ? `包${value}天` : `${value} Days`;
+}
+
+/**
+ * 智能格式化有效期后缀（用于价格展示）。
+ * - unit=month, value=1 → /月 / /mo
+ * - unit=month, value=3 → /3月 / /3mo
+ * - unit=week, value=2 → /2周 / /2wk
+ * - unit=day, value=30 → /月 / /mo
+ * - unit=day, value=90 → /90天 / /90d
+ */
+export function formatValiditySuffix(
+  value: number,
+  unit: ValidityUnit,
+  locale: 'zh' | 'en',
+): string {
+  if (unit === 'month') {
+    if (value === 1) return locale === 'zh' ? '/月' : '/mo';
+    return locale === 'zh' ? `/${value}月` : `/${value}mo`;
+  }
+  if (unit === 'week') {
+    if (value === 1) return locale === 'zh' ? '/周' : '/wk';
+    return locale === 'zh' ? `/${value}周` : `/${value}wk`;
+  }
+  // day
+  if (value === 30) return locale === 'zh' ? '/月' : '/mo';
+  return locale === 'zh' ? `/${value}天` : `/${value}d`;
+}
+
+/**
+ * 格式化有效期列表展示文本（管理后台表格用）。
+ * - unit=day → "30 天"
+ * - unit=week → "2 周"
+ * - unit=month → "1 月"
+ */
+export function formatValidityDisplay(
+  value: number,
+  unit: ValidityUnit,
+  locale: 'zh' | 'en',
+): string {
+  const unitLabels: Record<ValidityUnit, { zh: string; en: string }> = {
+    day: { zh: '天', en: 'day(s)' },
+    week: { zh: '周', en: 'week(s)' },
+    month: { zh: '月', en: 'month(s)' },
+  };
+  const label = locale === 'zh' ? unitLabels[unit].zh : unitLabels[unit].en;
+  return `${value} ${label}`;
+}