docs: add SaaS multi-tenant features and REST API overview

- Add SaaS multi-tenant section to both Chinese and English READMEs
- Add REST API endpoint reference table
- Add SaaS/plan highlights in subtitle and pain-point table
- Bilingual sync

Signed-off-by: Boos4721 <boos4721@icloud.com>

README.md

@@ -10,6 +10,8 @@
 汇聚成 <strong>一个 API Key、一个入口</strong>，自动发现模型、智能路由、成本最优。
 <br>
 <strong>内置 ComfyUI 对话助手</strong>，自然语言生成图像/视频工作流，开箱即用。
+<br>
+<strong>SaaS 多租户架构</strong>，组织管理、成员邀请、套餐限制，开箱即用。
 </p>
 
 <p align="center">
@@ -49,6 +51,8 @@
 | ✅ 每天签到领额度 | **自动签到** 定时执行，奖励自动追踪 |
 | 🤷 不知道各站有什么模型 | **自动模型发现**，上游新增模型零配置 |
 | 🎨 想用 ComfyUI 但不想配工作流 | **对话助手**，自然语言描述即可生成图像/视频 |
+| 👥 多人协作管理中转站 | **组织管理**，成员邀请，角色权限控制 |
+| 📋 不同团队需要不同配额 | **套餐系统**，Free/Pro/Enterprise 三级限制 |
 
 ---
 
@@ -115,6 +119,33 @@
 - 交互式聊天测试，流式/非流式双模式
 - 对比不同通道输出
 
+### 👥 SaaS 多租户管理
+
+- **组织管理**：创建组织，每个组织独立管理成员和配额
+- **成员邀请**：通过邮件邀请加入组织，支持管理员/成员角色
+- **三级套餐**：Free（3人）/ Pro（10人）/ Enterprise（100人）
+- **权限控制**：Owner / Admin / Member 三级角色，细粒度权限
+- **套餐限制检查**：成员数、API Key 数、日请求量自动限制
+- **邀请链接**：带 token 的邀请链接，48 小时有效期
+
+### 🔌 REST API 总览
+
+| 端点 | 方法 | 说明 |
+|------|------|------|
+| `/api/organizations` | GET/POST | 组织列表 / 创建组织 |
+| `/api/organizations/plans` | GET | 可用套餐列表 |
+| `/api/organizations/:id` | GET/PATCH | 组织详情 / 更新 |
+| `/api/organizations/:id/members` | GET | 成员列表 |
+| `/api/organizations/:id/members/:uid` | PATCH/DELETE | 改角色 / 移除成员 |
+| `/api/organizations/:id/invitations` | GET/POST | 邀请列表 / 创建邀请 |
+| `/api/organizations/:id/invitations/:invId` | DELETE | 撤销邀请 |
+| `/api/invitations/:token` | GET | 公开邀请查询 |
+| `/api/invitations/:token/accept` | POST | 接受邀请 |
+| `/api/users/register` | POST | 注册新用户 |
+| `/api/users/login` | POST | 登录获取 JWT |
+| `/api/users/me` | GET/PATCH | 个人信息 / 更新 |
+| `/api/user-api-keys` | GET/POST | API Key 列表 / 创建 |
+
 ---
 
 ## 🚀 快速开始

README_EN.md

@@ -10,6 +10,8 @@ Aggregate your New API / One API / OneHub / DoneHub / Veloera / AnyRouter / Sub2
 into <strong>one API Key, one endpoint</strong> — with auto model discovery, smart routing, and cost optimization.
 <br>
 <strong>Built-in ComfyUI chat assistant</strong> — generate images/videos from natural language, ready out of the box.
+<br>
+<strong>SaaS multi-tenant architecture</strong> — organization management, member invitations, plan limits.
 </p>
 
 <p align="center">
@@ -49,6 +51,8 @@ With the growing ecosystem of AI relay stations (New API / One API based), manag
 | ✅ Daily check-ins | **Auto check-in** with reward tracking |
 | 🤷 What models are available? | **Auto model discovery**, zero config |
 | 🎨 ComfyUI workflows too complex? | **Chat assistant**, describe in natural language |
+| 👥 Need multi-user access? | **Organizations**, member invites, role-based access |
+| 📋 Different teams need quotas? | **Plan system**, Free/Pro/Enterprise tiers |
 
 ---
 
@@ -98,12 +102,39 @@ With the growing ecosystem of AI relay stations (New API / One API based), manag
 - Scheduled refresh (default hourly), income/expense trends
 - Fallback estimation when API is unavailable
 
+### 👥 SaaS Multi-Tenant
+
+- **Organizations**: Create orgs, each with independent members and quotas
+- **Member Invitations**: Email-based invites with admin/member roles
+- **Three Plans**: Free (3 members) / Pro (10) / Enterprise (100)
+- **Role Control**: Owner / Admin / Member with granular permissions
+- **Plan Enforcement**: Auto-limit members, API keys, daily requests
+- **Invite Links**: Token-based, 48h expiry
+
 ### 🔔 Alerts & Notifications
 
 Five channels: Webhook / Bark / ServerChan / Telegram Bot / SMTP
 
 Scenarios: low balance, station failure, check-in failure, proxy errors, token expiry, daily digest
 
+### 🔌 REST API Overview
+
+| Endpoint | Method | Description |
+|----------|--------|-------------|
+| `/api/organizations` | GET/POST | List / Create org |
+| `/api/organizations/plans` | GET | List available plans |
+| `/api/organizations/:id` | GET/PATCH | Org detail / Update |
+| `/api/organizations/:id/members` | GET | List members |
+| `/api/organizations/:id/members/:uid` | PATCH/DELETE | Change role / Remove |
+| `/api/organizations/:id/invitations` | GET/POST | List / Create invite |
+| `/api/organizations/:id/invitations/:invId` | DELETE | Cancel invite |
+| `/api/invitations/:token` | GET | Public invite lookup |
+| `/api/invitations/:token/accept` | POST | Accept invitation |
+| `/api/users/register` | POST | Register new user |
+| `/api/users/login` | POST | Login (returns JWT) |
+| `/api/users/me` | GET/PATCH | Profile / Update |
+| `/api/user-api-keys` | GET/POST | List / Create API key |
+
 ---
 
 ## 🚀 Quick Start