fix(dashboard): приветствие без пустого имени для email-пользователей

src/utils/displayName.ts

@@ -3,21 +3,28 @@
  *
  * Why: single-letter first_name (e.g., "О") looked confusing alone ("Добро пожаловать, О!").
  * Combining with last_name makes truncated/short first names readable.
+ *
+ * Email/OAuth registration does not collect a name, so for such users every
+ * Telegram-derived field is null — fall back to the email local part
+ * ("vasya@gmail.com" → "vasya") to avoid an empty name in greetings.
  */
 export interface NameSource {
   first_name?: string | null;
   last_name?: string | null;
   username?: string | null;
   telegram_id?: number | null;
+  email?: string | null;
 }
 
 export function displayName(user?: NameSource | null): string {
   if (!user) return '';
   const fullName = [user.first_name, user.last_name]
-    .filter((part): part is string => Boolean(part && part.trim()))
+    .filter((part): part is string => Boolean(part?.trim()))
     .join(' ');
   if (fullName) return fullName;
   if (user.username) return user.username;
   if (user.telegram_id) return `#${user.telegram_id}`;
+  const emailLocalPart = user.email?.trim().split('@')[0];
+  if (emailLocalPart) return emailLocalPart;
   return '';
 }