Disallow empty custom user names

app/constants.ts

@@ -3,10 +3,16 @@ import type { BuildAbilitiesTupleWithUnknown } from "./modules/in-game-lists";
 export const TWEET_LENGTH_MAX_LENGTH = 280;
 export const DISCORD_MESSAGE_MAX_LENGTH = 2000;
 
+const EMPTY_CHARACTERS = ["\u200B", "\u200C", "\u200D", "\u200E", "\u200F"];
+export const notAllEmptyCharactersRegExp = new RegExp(
+	`^(?!(${EMPTY_CHARACTERS.join("|")})+$).*$`,
+);
+
 export const USER = {
 	BIO_MAX_LENGTH: DISCORD_MESSAGE_MAX_LENGTH,
 	CUSTOM_URL_MAX_LENGTH: 32,
 	CUSTOM_NAME_MAX_LENGTH: 32,
+	CUSTOM_NAME_REGEXP: notAllEmptyCharactersRegExp,
 	BATTLEFY_MAX_LENGTH: 32,
 	BSKY_MAX_LENGTH: 50,
 	IN_GAME_NAME_TEXT_MAX_LENGTH: 20,

app/features/user-page/routes/u.$identifier.edit.tsx

@@ -88,7 +88,12 @@ const userEditActionSchema = z
 		),
 		customName: z.preprocess(
 			falsyToNull,
-			z.string().trim().max(USER.CUSTOM_NAME_MAX_LENGTH).nullable(),
+			z
+				.string()
+				.trim()
+				.regex(USER.CUSTOM_NAME_REGEXP)
+				.max(USER.CUSTOM_NAME_MAX_LENGTH)
+				.nullable(),
 		),
 		battlefy: z.preprocess(
 			falsyToNull,