fix: Android APK 다운로드 window.open, CI npm ci 보강

@capacitor/browser 제거하고 네이티브 WebView에서 window.open 사용.
app node_modules 누락 시 root npm ci 실행.

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

scripts/build-mobile-apk.sh

@@ -64,7 +64,7 @@ fi
 log "google-services.json 확인"
 "$ROOT/scripts/ensure-android-google-services.sh"
 
-if [[ ! -d "$ROOT/node_modules/vite" ]]; then
+if [[ ! -d "$ROOT/node_modules/vite" ]] || [[ ! -d "$ROOT/app/node_modules/@capacitor/core" ]]; then
   log "npm ci (root dependencies)"
   (cd "$ROOT" && npm ci)
 fi