docs: add built-in payment configuration guide and update README

- Add docs/PAYMENT.md and docs/PAYMENT_CN.md with full payment setup guide
- Mark Sub2ApiPay as deprecated in ecosystem tables (payment is now built-in)
- Add built-in payment system to features list in all 3 READMEs

docs/PAYMENT.md

@@ -0,0 +1,272 @@
+# Payment System Configuration Guide
+
+Sub2API has a built-in payment system that enables user self-service top-up without deploying a separate payment service.
+
+---
+
+## Table of Contents
+
+- [Supported Payment Methods](#supported-payment-methods)
+- [Quick Start](#quick-start)
+- [System Settings](#system-settings)
+- [Provider Configuration](#provider-configuration)
+- [Provider Instance Management](#provider-instance-management)
+- [Webhook Configuration](#webhook-configuration)
+- [Payment Flow](#payment-flow)
+- [Migrating from Sub2ApiPay](#migrating-from-sub2apipay)
+
+---
+
+## Supported Payment Methods
+
+| Provider | Payment Methods | Description |
+|----------|----------------|-------------|
+| **EasyPay** | Alipay, WeChat Pay | Third-party aggregation via EasyPay protocol |
+| **Alipay (Direct)** | PC Page Pay, H5 Mobile Pay | Direct integration with Alipay Open Platform, auto-switches by device |
+| **WeChat Pay (Direct)** | Native QR Code, H5 Pay | Direct integration with WeChat Pay APIv3, mobile-first H5 |
+| **Stripe** | Card, Alipay, WeChat Pay, Link, etc. | International payments, multi-currency support |
+
+> Alipay/WeChat Pay direct and EasyPay can coexist. Direct channels connect to payment APIs directly with lower fees; EasyPay aggregates through third-party platforms with easier setup.
+
+---
+
+## Quick Start
+
+1. Go to Admin Dashboard → **Settings** → **Payment Settings** tab
+2. Enable **Payment**
+3. Configure basic parameters (amount range, timeout, etc.)
+4. Add at least one provider instance in **Provider Management**
+5. Users can now top up from the frontend
+
+---
+
+## System Settings
+
+Configure the following in Admin Dashboard **Settings → Payment Settings**:
+
+### Basic Settings
+
+| Setting | Description | Default |
+|---------|-------------|---------|
+| **Enable Payment** | Enable or disable the payment system | Off |
+| **Product Name Prefix** | Prefix shown on payment page | - |
+| **Product Name Suffix** | Suffix (e.g., "Credits") | - |
+| **Minimum Amount** | Minimum single top-up amount | 1 |
+| **Maximum Amount** | Maximum single top-up amount (empty = unlimited) | - |
+| **Daily Limit** | Per-user daily cumulative limit (empty = unlimited) | - |
+| **Order Timeout** | Order timeout in minutes (minimum 1) | 5 |
+| **Max Pending Orders** | Maximum concurrent pending orders per user | 3 |
+| **Load Balance Strategy** | Strategy for selecting provider instances | Least Amount |
+
+### Load Balance Strategies
+
+| Strategy | Description |
+|----------|-------------|
+| **Round Robin** | Distribute orders to instances in rotation |
+| **Least Amount** | Prefer instances with the lowest daily cumulative amount |
+
+### Cancel Rate Limiting
+
+Prevents users from repeatedly creating and canceling orders:
+
+| Setting | Description |
+|---------|-------------|
+| **Enable Limit** | Toggle |
+| **Window Mode** | Sliding / Fixed window |
+| **Time Window** | Window duration |
+| **Window Unit** | Minutes / Hours |
+| **Max Cancels** | Maximum cancellations allowed within the window |
+
+### Help Information
+
+| Setting | Description |
+|---------|-------------|
+| **Help Image** | Customer service QR code or help image (supports upload) |
+| **Help Text** | Instructions displayed on the payment page |
+
+---
+
+## Provider Configuration
+
+Each provider type requires different credentials. Select the type when adding a new provider instance in **Provider Management → Add Provider**.
+
+### EasyPay
+
+Compatible with any payment service that implements the EasyPay protocol.
+
+| Parameter | Description | Required |
+|-----------|-------------|----------|
+| **Merchant ID (PID)** | EasyPay merchant ID | Yes |
+| **Merchant Key (PKey)** | EasyPay merchant secret key | Yes |
+| **API Base URL** | EasyPay API base address | Yes |
+| **Notify URL** | Async callback URL for payment success | Yes |
+| **Return URL** | Redirect URL after payment completion | No |
+| **Alipay Channel ID** | Specify Alipay channel (optional) | No |
+| **WeChat Channel ID** | Specify WeChat channel (optional) | No |
+
+### Alipay (Direct)
+
+Direct integration with Alipay Open Platform. Supports PC page pay and H5 mobile pay.
+
+| Parameter | Description | Required |
+|-----------|-------------|----------|
+| **AppID** | Alipay application AppID | Yes |
+| **Private Key** | RSA2 application private key | Yes |
+| **Alipay Public Key** | Alipay public key | Yes |
+| **Notify URL** | Async callback URL | Yes |
+| **Return URL** | Redirect URL after payment | No |
+
+### WeChat Pay (Direct)
+
+Direct integration with WeChat Pay APIv3. Supports Native QR code and H5 payment.
+
+| Parameter | Description | Required |
+|-----------|-------------|----------|
+| **AppID** | WeChat Pay AppID | Yes |
+| **Merchant ID (MchID)** | WeChat Pay merchant ID | Yes |
+| **Merchant API Private Key** | Merchant API private key (PEM format) | Yes |
+| **Certificate Serial Number** | Merchant certificate serial number | Yes |
+| **APIv3 Key** | 32-byte APIv3 key | Yes |
+| **WeChat Pay Public Key** | WeChat Pay public key (PEM format) | Yes |
+| **WeChat Pay Public Key ID** | WeChat Pay public key ID | Yes |
+| **Notify URL** | Async callback URL | Yes |
+
+### Stripe
+
+International payment platform supporting multiple payment methods and currencies.
+
+| Parameter | Description | Required |
+|-----------|-------------|----------|
+| **Secret Key** | Stripe secret key (`sk_live_...` or `sk_test_...`) | Yes |
+| **Publishable Key** | Stripe publishable key (`pk_live_...` or `pk_test_...`) | Yes |
+| **Webhook Secret** | Stripe Webhook signing secret (`whsec_...`) | Yes |
+
+---
+
+## Provider Instance Management
+
+You can create **multiple instances** of the same provider type for load balancing and risk control:
+
+- **Multi-instance load balancing** — Distribute orders via round-robin or least-amount strategy
+- **Independent limits** — Each instance can have its own min/max amount and daily limit
+- **Independent toggle** — Enable/disable individual instances without affecting others
+- **Refund control** — Enable or disable refunds per instance
+- **Payment methods** — Each instance can support a subset of payment methods
+- **Ordering** — Drag to reorder instances
+
+### Instance Limit Configuration
+
+Each instance supports these limits:
+
+| Limit | Description |
+|-------|-------------|
+| **Minimum Amount** | Minimum order amount accepted by this instance |
+| **Maximum Amount** | Maximum order amount accepted by this instance |
+| **Daily Limit** | Daily cumulative transaction limit for this instance |
+
+> During load balancing, instances that exceed their limits are automatically skipped.
+
+---
+
+## Webhook Configuration
+
+Payment callbacks are essential for the payment system to work correctly.
+
+### Callback URL Format
+
+| Provider | Callback URL |
+|----------|-------------|
+| **EasyPay** | `https://your-domain.com/api/v1/payment/easypay/notify` |
+| **Alipay (Direct)** | `https://your-domain.com/api/v1/payment/alipay/notify` |
+| **WeChat Pay (Direct)** | `https://your-domain.com/api/v1/payment/wxpay/notify` |
+| **Stripe** | `https://your-domain.com/api/v1/payment/stripe/webhook` |
+
+> Replace `your-domain.com` with your actual domain.
+
+### Stripe Webhook Setup
+
+1. Log in to [Stripe Dashboard](https://dashboard.stripe.com/)
+2. Go to **Developers → Webhooks**
+3. Add an endpoint with the callback URL
+4. Subscribe to events: `payment_intent.succeeded`, `payment_intent.payment_failed`
+5. Copy the generated Webhook Secret (`whsec_...`) to your provider configuration
+
+### Important Notes
+
+- Callback URLs must use **HTTPS** (required by Stripe, strongly recommended for others)
+- Ensure your firewall allows callback requests from payment platforms
+- The system automatically verifies callback signatures to prevent forgery
+- Balance top-up is processed automatically upon successful payment — no manual intervention needed
+
+---
+
+## Payment Flow
+
+```
+User selects amount and payment method
+       │
+       ▼
+  Create Order (PENDING)
+  ├─ Validate amount range, pending order count, daily limit
+  ├─ Load balance to select provider instance
+  └─ Call provider to get payment info
+       │
+       ▼
+  User completes payment
+  ├─ EasyPay     → QR code / H5 redirect
+  ├─ Alipay      → PC page pay / H5 mobile pay
+  ├─ WeChat Pay  → Native QR / H5 pay
+  └─ Stripe      → Payment Element (card/Alipay/WeChat/etc.)
+       │
+       ▼
+  Webhook callback verified → Order PAID
+       │
+       ▼
+  Auto top-up to user balance → Order COMPLETED
+```
+
+### Order Status Reference
+
+| Status | Description |
+|--------|-------------|
+| `PENDING` | Waiting for user to complete payment |
+| `PAID` | Payment confirmed, awaiting balance credit |
+| `COMPLETED` | Balance credited successfully |
+| `EXPIRED` | Timed out without payment |
+| `CANCELLED` | Cancelled by user |
+| `FAILED` | Balance credit failed, admin can retry |
+| `REFUND_REQUESTED` | Refund requested |
+| `REFUNDING` | Refund in progress |
+| `REFUNDED` | Refund completed |
+
+### Timeout and Fallback
+
+- Before marking an order as expired, the background job queries the upstream payment status first
+- If the user has actually paid but the callback was delayed, the system will reconcile automatically
+- The background job runs every 60 seconds to check for timed-out orders
+
+---
+
+## Migrating from Sub2ApiPay
+
+If you previously used [Sub2ApiPay](https://github.com/touwaeriol/sub2apipay) as an external payment system, you can migrate to the built-in payment system:
+
+### Key Differences
+
+| Aspect | Sub2ApiPay | Built-in Payment |
+|--------|-----------|-----------------|
+| Deployment | Separate service (Next.js + PostgreSQL) | Built into Sub2API, no extra deployment |
+| Payment Methods | EasyPay, Alipay, WeChat, Stripe | Same |
+| Configuration | Environment variables + separate admin UI | Unified in Sub2API admin dashboard |
+| Top-up Integration | Via Admin API callback | Internal processing, more reliable |
+| Subscription Plans | Supported | Not yet (planned) |
+| Order Management | Separate admin interface | Integrated in Sub2API admin dashboard |
+
+### Migration Steps
+
+1. Enable payment in Sub2API admin dashboard and configure providers (use the same payment credentials)
+2. Update webhook callback URLs to Sub2API's callback endpoints
+3. Verify that new orders are processed correctly via built-in payment
+4. Decommission the Sub2ApiPay service
+
+> **Note**: Historical order data from Sub2ApiPay will not be automatically migrated. Keep Sub2ApiPay running for a while to access historical records.

docs/PAYMENT_CN.md

@@ -0,0 +1,274 @@
+# 支付系统配置指南
+
+Sub2API 内置支付系统，支持用户自助充值，无需部署独立的支付服务。
+
+---
+
+## 目录
+
+- [支持的支付方式](#支持的支付方式)
+- [快速开始](#快速开始)
+- [系统设置](#系统设置)
+- [服务商配置](#服务商配置)
+- [服务商实例管理](#服务商实例管理)
+- [Webhook 配置](#webhook-配置)
+- [支付流程](#支付流程)
+- [从 Sub2ApiPay 迁移](#从-sub2apipay-迁移)
+
+---
+
+## 支持的支付方式
+
+| 服务商 | 支付方式 | 说明 |
+|--------|---------|------|
+| **EasyPay（易支付）** | 支付宝、微信支付 | 兼容易支付协议的第三方聚合支付 |
+| **支付宝官方** | 支付宝 PC 页面支付、H5 手机网站支付 | 直接对接支付宝开放平台，自动根据终端切换 |
+| **微信官方** | Native 扫码支付、H5 支付 | 直接对接微信支付 APIv3，移动端优先 H5 |
+| **Stripe** | 银行卡、支付宝、微信支付、Link 等 | 国际支付，支持多币种 |
+
+> 支付宝官方 / 微信官方与 EasyPay 可以共存。官方渠道直接对接 API，资金直达商户账户，手续费更低；EasyPay 通过第三方平台聚合，接入门槛更低。
+
+---
+
+## 快速开始
+
+1. 进入管理后台 → **设置** → **支付设置** 标签页
+2. 开启 **启用支付**
+3. 配置基本参数（金额范围、超时时间等）
+4. 在 **服务商管理** 中添加至少一个服务商实例
+5. 用户即可在前端页面进行充值
+
+---
+
+## 系统设置
+
+在管理后台 **设置 → 支付设置** 中配置以下参数：
+
+### 基本设置
+
+| 设置项 | 说明 | 默认值 |
+|--------|------|--------|
+| **启用支付** | 启用或禁用支付系统 | 关闭 |
+| **商品名前缀** | 支付页面显示的商品名前缀 | - |
+| **商品名后缀** | 商品名后缀（如"元"） | - |
+| **最低金额** | 单笔最低充值金额 | 1 |
+| **最高金额** | 单笔最高充值金额（留空表示不限制） | - |
+| **每日限额** | 每用户每日累计充值上限（留空表示不限制） | - |
+| **订单超时时间** | 订单超时分钟数，至少 1 分钟 | 5 |
+| **最大待支付订单数** | 同一用户最大并行待支付订单数 | 3 |
+| **负载均衡策略** | 多服务商实例时的选择策略 | 最少金额 |
+
+### 负载均衡策略
+
+| 策略 | 说明 |
+|------|------|
+| **轮询（round-robin）** | 按顺序轮流分配到各服务商实例 |
+| **最少金额（least-amount）** | 优先分配到当日累计金额最少的实例 |
+
+### 取消频率限制
+
+防止用户频繁创建并取消订单：
+
+| 设置项 | 说明 |
+|--------|------|
+| **启用限制** | 开关 |
+| **窗口模式** | 滚动窗口 / 固定窗口 |
+| **时间窗口** | 窗口长度 |
+| **窗口单位** | 分钟 / 小时 |
+| **最大次数** | 窗口内允许的最大取消次数 |
+
+### 帮助信息
+
+| 设置项 | 说明 |
+|--------|------|
+| **帮助图片** | 充值页面显示的客服二维码等图片（支持上传） |
+| **帮助文本** | 充值页面显示的说明文字 |
+
+---
+
+## 服务商配置
+
+每种服务商需要不同的凭证和参数。在 **服务商管理 → 添加服务商** 中选择类型后填写。
+
+### EasyPay（易支付）
+
+兼容任何 EasyPay 协议的支付服务商。
+
+| 参数 | 说明 | 必填 |
+|------|------|------|
+| **商户 ID（PID）** | EasyPay 商户 ID | 是 |
+| **商户密钥（PKey）** | EasyPay 商户密钥 | 是 |
+| **API 地址** | EasyPay API 基础地址 | 是 |
+| **异步回调地址** | 支付成功后的回调 URL | 是 |
+| **同步跳转地址** | 支付完成后的跳转 URL | 否 |
+| **支付宝通道 ID** | 指定支付宝通道（可选） | 否 |
+| **微信通道 ID** | 指定微信通道（可选） | 否 |
+
+> **EasyPay 推荐**：[ZPay](https://z-pay.cn) 支持个人用户（无营业执照）每日 1 万元以内交易。支付渠道的安全性和合规性请自行鉴别。
+
+### 支付宝官方
+
+直接对接支付宝开放平台，支持 PC 页面支付和 H5 手机网站支付。
+
+| 参数 | 说明 | 必填 |
+|------|------|------|
+| **AppID** | 支付宝应用 AppID | 是 |
+| **应用私钥** | RSA2 应用私钥 | 是 |
+| **支付宝公钥** | 支付宝公钥 | 是 |
+| **异步回调地址** | 支付成功后的回调 URL | 是 |
+| **同步跳转地址** | 支付完成后的跳转 URL | 否 |
+
+### 微信官方
+
+直接对接微信支付 APIv3，支持 Native 扫码支付和 H5 支付。
+
+| 参数 | 说明 | 必填 |
+|------|------|------|
+| **AppID** | 微信支付 AppID | 是 |
+| **商户号（MchID）** | 微信支付商户号 | 是 |
+| **商户 API 私钥** | 商户 API 私钥（PEM 格式） | 是 |
+| **商户证书序列号** | 商户证书序列号 | 是 |
+| **APIv3 密钥** | 32 位 APIv3 密钥 | 是 |
+| **微信支付公钥** | 微信支付公钥（PEM 格式） | 是 |
+| **微信支付公钥 ID** | 微信支付公钥 ID | 是 |
+| **异步回调地址** | 支付成功后的回调 URL | 是 |
+
+### Stripe
+
+国际支付平台，支持多种支付方式和币种。
+
+| 参数 | 说明 | 必填 |
+|------|------|------|
+| **Secret Key** | Stripe 密钥（`sk_live_...` 或 `sk_test_...`） | 是 |
+| **Publishable Key** | Stripe 可公开密钥（`pk_live_...` 或 `pk_test_...`） | 是 |
+| **Webhook Secret** | Stripe Webhook 签名密钥（`whsec_...`） | 是 |
+
+---
+
+## 服务商实例管理
+
+同一种服务商可以创建**多个实例**，实现负载均衡和风控：
+
+- **多实例负载均衡** — 按轮询或最少金额策略分流订单
+- **独立限额** — 每个实例可独立配置单笔最小/最大金额和每日限额
+- **独立启停** — 可单独启用/禁用某个实例，不影响其他实例
+- **退款控制** — 每个实例可单独开启或关闭退款功能
+- **支付方式** — 每个实例可选择支持的支付方式子集
+- **排序** — 拖拽调整实例顺序
+
+### 实例限额配置
+
+每个实例支持以下限额：
+
+| 限额项 | 说明 |
+|--------|------|
+| **单笔最小金额** | 该实例接受的最小订单金额 |
+| **单笔最大金额** | 该实例接受的最大订单金额 |
+| **每日限额** | 该实例每日累计交易上限 |
+
+> 负载均衡时，系统会自动跳过超出限额的实例。
+
+---
+
+## Webhook 配置
+
+支付回调是支付系统的核心环节，必须正确配置：
+
+### 回调地址格式
+
+| 服务商 | 回调地址 |
+|--------|---------|
+| **EasyPay** | `https://your-domain.com/api/v1/payment/easypay/notify` |
+| **支付宝官方** | `https://your-domain.com/api/v1/payment/alipay/notify` |
+| **微信官方** | `https://your-domain.com/api/v1/payment/wxpay/notify` |
+| **Stripe** | `https://your-domain.com/api/v1/payment/stripe/webhook` |
+
+> 将 `your-domain.com` 替换为你的实际域名。
+
+### Stripe Webhook 设置
+
+1. 登录 [Stripe Dashboard](https://dashboard.stripe.com/)
+2. 进入 **Developers → Webhooks**
+3. 添加端点，填写回调地址
+4. 订阅事件：`payment_intent.succeeded`、`payment_intent.payment_failed`
+5. 将生成的 Webhook Secret（`whsec_...`）填入服务商配置
+
+### 注意事项
+
+- 回调地址必须是 **HTTPS**（Stripe 强制要求，其他服务商强烈推荐）
+- 确保服务器防火墙允许支付平台的回调请求
+- 系统会自动进行签名验证，防止伪造回调
+- 支付成功后自动完成余额充值，无需人工干预
+
+---
+
+## 支付流程
+
+```
+用户选择充值金额和支付方式
+       │
+       ▼
+  创建订单 (PENDING)
+  ├─ 校验金额范围、待支付订单数、每日限额
+  ├─ 负载均衡选择服务商实例
+  └─ 调用服务商获取支付信息
+       │
+       ▼
+  用户完成支付
+  ├─ EasyPay    → 扫码 / H5 跳转
+  ├─ 支付宝官方  → PC 页面支付 / H5 手机网站支付
+  ├─ 微信官方    → Native 扫码 / H5 支付
+  └─ Stripe     → Payment Element（银行卡/支付宝/微信等）
+       │
+       ▼
+  支付回调验签 → 订单 PAID
+       │
+       ▼
+  自动充值到用户余额 → 订单 COMPLETED
+```
+
+### 订单状态说明
+
+| 状态 | 说明 |
+|------|------|
+| `PENDING` | 待支付，等待用户完成支付 |
+| `PAID` | 已支付，等待充值到账 |
+| `COMPLETED` | 已完成，余额已到账 |
+| `EXPIRED` | 已过期，超时未支付 |
+| `CANCELLED` | 已取消，用户主动取消 |
+| `FAILED` | 充值失败，可管理员重试 |
+| `REFUND_REQUESTED` | 已申请退款 |
+| `REFUNDING` | 退款处理中 |
+| `REFUNDED` | 已退款 |
+
+### 超时与兜底
+
+- 订单超时后，后台任务会先查询上游支付状态再标记过期
+- 如果用户实际已支付但回调延迟，系统会通过查询补单
+- 后台任务每 60 秒执行一次超时检查
+
+---
+
+## 从 Sub2ApiPay 迁移
+
+如果你之前使用 [Sub2ApiPay](https://github.com/touwaeriol/sub2apipay) 作为外部支付系统，现在可以迁移到内置支付：
+
+### 主要差异
+
+| 对比项 | Sub2ApiPay | 内置支付 |
+|--------|-----------|---------|
+| 部署方式 | 独立服务（Next.js + PostgreSQL） | 内置于 Sub2API，无需额外部署 |
+| 支付方式 | EasyPay、支付宝、微信、Stripe | 相同 |
+| 配置方式 | 环境变量 + 独立管理后台 | Sub2API 管理后台内统一配置 |
+| 充值对接 | 通过 Admin API 回调 | 内部直接处理，更可靠 |
+| 订阅套餐 | 支持 | 暂不支持（计划中） |
+| 订单管理 | 独立管理界面 | 集成在 Sub2API 管理后台 |
+
+### 迁移步骤
+
+1. 在 Sub2API 管理后台启用支付并配置服务商（使用相同的支付凭证）
+2. 更新 Webhook 回调地址为 Sub2API 的回调地址
+3. 确认新订单通过内置支付正常处理
+4. 停用 Sub2ApiPay 服务
+
+> **注意**：Sub2ApiPay 中的历史订单数据不会自动迁移。建议保留 Sub2ApiPay 一段时间以便查询历史记录。