从头构建并签名 JWT 令牌,支持 HMAC-SHA256 或创建未签名令牌
{ "alg": "HS256", "typ": "JWT" }
{ "sub": 1234567890, "name": "John Doe" }
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOjEyMzQ1Njc4OTAsIm5hbWUiOiJKb2huIERvZSJ9
Click "Sign Token" to generate the signed JWT.