fix: desktop updater signing in non-interactive CI

Use --ci for key generation and pass empty password to tauri signer sign
so Jenkins/SSH builds can sign updater bundles without a TTY.

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

scripts/setup-desktop-updater-keys.sh

@@ -17,7 +17,7 @@ if [[ -f "$KEY_PATH" ]]; then
   echo "기존 private key: $KEY_PATH"
 else
   echo "새 updater 키 생성: $KEY_PATH"
-  GEN_OUT="$(cd "$DESKTOP_DIR" && npx tauri signer generate -w "$KEY_PATH" -f 2>&1)" || true
+  GEN_OUT="$(cd "$DESKTOP_DIR" && CI=1 npx tauri signer generate -w "$KEY_PATH" -f --ci 2>&1)" || true
   echo "$GEN_OUT"
   if [[ ! -f "$KEY_PATH" ]]; then
     echo "키 생성 실패. Rust/tauri-cli 확인 후 재시도."