feat: Complete localization system with i18n and DeepSeek AI translation

🌐 Interface Localization:
- Added i18next for multi-language interface support
- Created LocalizationService with language detection
- Added translation files for Russian and English
- Implemented language selection in user settings

🤖 AI Profile Translation (Premium feature):
- Integrated DeepSeek API for profile translation
- Added TranslationController for translation management
- Premium-only access to profile translation feature
- Support for 10 languages (ru, en, es, fr, de, it, pt, zh, ja, ko)

�� Database & Models:
- Added language field to users table with migration
- Updated User model to support language preferences
- Added language constraints and indexing

🎛️ User Interface:
- Added language settings menu in bot settings
- Implemented callback handlers for language selection
- Added translate profile button for VIP users
- Localized all interface strings

📚 Documentation:
- Created comprehensive LOCALIZATION.md guide
- Documented API usage and configuration
- Added examples for extending language support

src/models/User.ts

@@ -5,6 +5,7 @@ export interface UserData {
     firstName?: string;
     lastName?: string;
     languageCode?: string;
+    language?: string; // Предпочитаемый язык интерфейса
     isActive: boolean;
     createdAt: Date;
     lastActiveAt: Date;
@@ -17,6 +18,7 @@ export class User {
     firstName?: string;
     lastName?: string;
     languageCode?: string;
+    language: string; // Предпочитаемый язык интерфейса
     isActive: boolean;
     createdAt: Date;
     lastActiveAt: Date;
@@ -28,6 +30,7 @@ export class User {
         this.firstName = data.firstName;
         this.lastName = data.lastName;
         this.languageCode = data.languageCode || 'en';
+        this.language = data.language || 'ru'; // Язык интерфейса по умолчанию
         this.isActive = data.isActive;
         this.createdAt = data.createdAt;
         this.lastActiveAt = data.lastActiveAt;
@@ -67,4 +70,14 @@ export class User {
         this.isActive = true;
         this.updateLastActive();
     }
+
+    // Установить язык интерфейса
+    setLanguage(language: string): void {
+        this.language = language;
+    }
+
+    // Получить язык интерфейса
+    getLanguage(): string {
+        return this.language;
+    }
 }