对外接入只需要两步：先调用邀请注册接口拿到用户信息和默认 API Key，再使用这个 API Key 调用 OpenAI 兼容的 AI 接口。

用于第三方自动开户。必须传入 inviter_id、email 和 key_name。系统会按该用户+key_name 查找 API Key，不存在则自动创建并返回。

POST /api/auth/register
Content-Type: application/json

{
  "email": "user@example.com",
  "inviter_id": 10001,
  "key_name": "goodhr"
}

{
  "code": 0,
  "message": "success",
  "data": {
    "user": {
      "id": 20001,
      "email": "user@example.com",
      "nickname": "user",
      "role": "user",
      "inviter_id": 10001
    },
    "api_key": {
      "id": 30001,
      "name": "goodhr",
      "key": "sk-xxxx",
      "key_prefix": "sk-xxxx"
    },
    "balance": "0.2",
    "cny_balance": "1.44",
    "is_new_user": true
  }
}

对外调用走 OpenAI 兼容接口。拿到注册接口返回的 API Key 后，直接请求 `/v1/chat/completions`、`/v1/embeddings`、`/v1/images/generations` 等接口即可。

POST /v1/chat/completions
Content-Type: application/json
Authorization: Bearer sk-xxxx

{
  "model": "gpt-4o",
  "messages": [
    {
      "role": "user",
      "content": "你好，帮我写一段产品介绍"
    }
  ]
}

{
  "id": "chatcmpl-xxx",
  "object": "chat.completion",
  "created": 1776746375,
  "model": "gpt-4o",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "这里是生成结果"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 12,
    "completion_tokens": 48,
    "total_tokens": 60
  }
}