Feature: Russian language support & Vehicle Requests improvements

- Add Russian language support (title_ru, subtitle_ru) for hero banners
- Add fuel/transmission translations for Mongolian (경유→Дизель, 오토→Автомат)
- Improve Vehicle Requests admin page:
  - Display real request ID and user email
  - Show detailed request info (maker, grade, year, fuel, mileage)
  - Replace modal search with Cars page integration
- Add "Add to Request" flow in Cars page for vehicle recommendations
- Fix image URL handling in FilmStripSlider and car detail page

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/types/index.ts

@@ -134,10 +134,12 @@ export interface HeroBanner {
   title_ko?: string;
   title_en?: string;
   title_mn?: string;
+  title_ru?: string;  // 러시아어
   // 다국어 서브타이틀 (Admin API 응답)
   subtitle_ko?: string;
   subtitle_en?: string;
   subtitle_mn?: string;
+  subtitle_ru?: string;  // 러시아어
   // 로컬라이즈된 필드 (Public API 응답)
   title?: string;
   subtitle?: string;