feat: Phase 1 mobile tablet — Jenkins APK, PC tab, in-app update

Capacitor 확장으로 git push 시 Mobile Jenkins 빌드, PC 탭 Android/iPad 다운로드,
앱 내 APK 업데이트, iOS TestFlight API 및 Capacitor ios 프로젝트를 추가한다.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/utils/backendApi.ts

@@ -637,6 +637,8 @@ export interface MobileAppReleaseInfoDto {
   updatedAt?: string;
   downloadUrl?: string;
   installPageUrl?: string;
+  iosAvailable?: boolean;
+  iosTestFlightUrl?: string;
 }
 
 export async function loadMobileAppReleaseInfo(): Promise<MobileAppReleaseInfoDto | null> {