deploy: persist self-hosted APK downloads across atomic webroot swaps

EAS preview APK is staged at /opt/kintex/downloads and reinjected into the
web root during deploy, keeping /downloads/kintex.apk (QR install page) alive.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

deploy/deploy_kintex.sh

@@ -47,6 +47,13 @@ log "프론트 빌드 검증 통과(${#REFS[@]} assets)"
 STAGE="${WEB_ROOT}.new.$$"
 rm -rf "$STAGE"; mkdir -p "$STAGE"
 cp -r "$DIST/." "$STAGE/"
+# APK 자체 호스팅 영속화 — dist 에 없는 /downloads(EAS APK)를 스테이징에 주입해
+# 원자 교체 후에도 QR 다운로드(/downloads/kintex.apk)가 유지되게 한다. 원본은 /opt/kintex/downloads.
+if [ -d /opt/kintex/downloads ]; then
+  mkdir -p "$STAGE/downloads"
+  cp -a /opt/kintex/downloads/. "$STAGE/downloads/" || log "WARN: APK downloads 주입 실패(계속)"
+  log "APK downloads 주입(/opt/kintex/downloads → 웹루트)"
+fi
 if [ -d "$WEB_ROOT" ] && [ -n "$(ls -A "$WEB_ROOT" 2>/dev/null)" ]; then
   tar czf "/var/www/kintex.bak_$(date +%Y%m%d_%H%M%S).tgz" -C "$WEB_ROOT" . || log "WARN: 프론트 백업 실패(계속)"
 fi