feat(auth): add username sign-in mode and recovery kits (#3215)

fluxer_api/src/api/utils/GuildVerificationUtils.ts

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
 import {createRoleIDSet, createUserID, type RoleID, type UserID} from '@app/api/BrandedTypes';
+import {usesUsernameSignIn} from '@app/api/instance/AccountIdentityModeCache';
 import type {Guild} from '@app/api/models/Guild';
 import type {GuildMember} from '@app/api/models/GuildMember';
 import type {User} from '@app/api/models/User';
@@ -39,12 +40,18 @@ function checkGuildVerification(params: VerificationParams): void {
 	if (memberRoles && memberRoles.size > 0) {
 		return;
 	}
-	if (!user.email) {
-		throw new GuildVerificationRequiredError('You need to claim your account to send messages in this guild.');
-	}
-	if (verificationLevel >= GuildVerificationLevel.LOW) {
-		if (!user.emailVerified) {
-			throw new GuildEmailVerificationRequiredError();
+	if (usesUsernameSignIn()) {
+		if (user.isUnclaimedAccount()) {
+			throw new GuildVerificationRequiredError('You need to claim your account to send messages in this guild.');
+		}
+	} else {
+		if (!user.email) {
+			throw new GuildVerificationRequiredError('You need to claim your account to send messages in this guild.');
+		}
+		if (verificationLevel >= GuildVerificationLevel.LOW) {
+			if (!user.emailVerified) {
+				throw new GuildEmailVerificationRequiredError();
+			}
 		}
 	}
 	if (verificationLevel >= GuildVerificationLevel.MEDIUM) {

fluxer_api/src/api/utils/UsernameSuggestionUtils.ts

@@ -5,16 +5,21 @@ import {transliterate as tr} from 'transliteration';
 
 const MAX_USERNAME_LENGTH = 32;
 
-function sanitizeDisplayName(globalName: string): string | null {
-	const trimmed = globalName.trim();
-	if (!trimmed) return null;
+export function normaliseUsernameCandidate(value: string): string {
+	const trimmed = value.trim();
+	if (!trimmed) return '';
 	let sanitized = tr(trimmed);
 	sanitized = sanitized.replace(/[\s\-.]+/g, '_');
 	sanitized = sanitized.replace(/[^a-zA-Z0-9_]/g, '');
-	if (!sanitized) return null;
 	if (sanitized.length > MAX_USERNAME_LENGTH) {
 		sanitized = sanitized.substring(0, MAX_USERNAME_LENGTH);
 	}
+	return sanitized;
+}
+
+function sanitizeDisplayName(globalName: string): string | null {
+	const sanitized = normaliseUsernameCandidate(globalName);
+	if (!sanitized) return null;
 	const validation = UsernameType.safeParse(sanitized);
 	if (!validation.success) {
 		return null;