[WIP] feat: Custom Error Component support errorCode in client side

[evenchange4]

// page.tsx
export const loader = async ctx => {
  return ctx.error('michael-error', 404);
};

// src/error.tsx
export default function Error(props) {
  // before: props.errorCode is undefined in client side
+ // after: props.errorCode is now defined 404 in client side
}