POST /activate
Request:
POST https://activate.jindouzi.net/activate
Content-Type: application/json
{"device_id": "your-device-unique-id"}
Response 200:
{"activation_code": "RSA签名..."}
Response 400:
{"error": "invalid device_id"}
device_id: 8-256 字符，建议 SHA256(设备硬件信息)