Login: no guest option; every user signs in with a phone number

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/lib/storage.ts

@@ -24,21 +24,8 @@ export const store = {
 };
 
 export const KEYS = {
-  deviceId: 'deviceId',
   onboarded: 'tadrisino.onboarded',
   conversationId: 'tadrisino.conversationId',
   sound: 'tadrisino.sound',
   referralCode: 'tadrisino.referralCode',
 } as const;
-
-/** شناسه‌ی ثابتِ این مرورگر برای ورودِ مهمان. */
-export function getDeviceId(): string {
-  let id = store.get(KEYS.deviceId);
-  if (!id) {
-    id = globalThis.crypto && 'randomUUID' in crypto
-      ? crypto.randomUUID()
-      : `${Date.now()}-${Math.random().toString(36).slice(2)}`;
-    store.set(KEYS.deviceId, id);
-  }
-  return id;
-}