Merge PR #506: приветствие без пустого имени для email-пользователей

displayName() получил фолбэк на локальную часть email; без имени вовсе —
dashboard.welcomeNoName без запятой (4 локали). Закрывает #423.
Спасибо @kewldan.

src/utils/displayName.test.ts

@@ -0,0 +1,51 @@
+import { describe, expect, it } from 'vitest';
+import { displayName } from './displayName';
+
+describe('displayName', () => {
+  it('returns empty string for missing user', () => {
+    expect(displayName(undefined)).toBe('');
+    expect(displayName(null)).toBe('');
+  });
+
+  it('combines first_name and last_name', () => {
+    expect(displayName({ first_name: 'Иван', last_name: 'Петров' })).toBe('Иван Петров');
+    expect(displayName({ first_name: 'Иван', last_name: null })).toBe('Иван');
+    expect(displayName({ first_name: null, last_name: 'Петров' })).toBe('Петров');
+  });
+
+  it('falls back to username when there is no name', () => {
+    expect(displayName({ first_name: null, last_name: null, username: 'ivan' })).toBe('ivan');
+  });
+
+  it('falls back to telegram_id when there is no name and no username', () => {
+    expect(displayName({ first_name: null, username: null, telegram_id: 123456 })).toBe('#123456');
+  });
+
+  it('falls back to the email local part for email-only users', () => {
+    expect(
+      displayName({
+        first_name: null,
+        last_name: null,
+        username: null,
+        telegram_id: null,
+        email: 'vasya@gmail.com',
+      }),
+    ).toBe('vasya');
+  });
+
+  it('prefers telegram_id over email', () => {
+    expect(displayName({ telegram_id: 123456, email: 'vasya@gmail.com' })).toBe('#123456');
+  });
+
+  it('returns empty string when every source is empty', () => {
+    expect(
+      displayName({
+        first_name: '  ',
+        last_name: null,
+        username: null,
+        telegram_id: null,
+        email: null,
+      }),
+    ).toBe('');
+  });
+});

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 '';
 }