do not throw 500 on mojang server error

src/lib/server/minecraft.ts

@@ -1,17 +1,22 @@
 import { createHash } from 'node:crypto';
 
 export class UserNotFoundError extends Error {
+	readonly username: string;
+
 	constructor(username: string) {
-		super(`Ein Spieler mit dem Namen '${username}' konnte nicht gefunden werden`);
+		super(`couldn't find a player with the username '${username}'`);
+		this.username = username;
 	}
 }
 
+export class MojangError extends Error {}
+
 export async function getJavaUuid(username: string): Promise<string> {
 	const response = await fetch(`https://api.mojang.com/users/profiles/minecraft/${username}`);
 	if (!response.ok) {
 		throw response.status < 500
 			? new UserNotFoundError(username)
-			: new Error(`mojang server error (${response.status}): ${await response.text()}`);
+			: new MojangError(`mojang server error (${response.status}): ${await response.text()}`);
 	}
 	const json = await response.json();
 	const id: string = json['id'];