fix: run Railpack install with sudo during remote deploy

Deploy-time Railpack install ran without sudo, so deploys to a remote
server with a non-root user (passwordless sudo) failed because the
install script could not write to /usr/local/bin ("A terminal is
required to authenticate").

Detect whether sudo is needed (root vs. passwordless-sudo user) and run
the install through it, matching the server-setup script.

Fixes #5007

packages/server/src/utils/builders/railpack.ts

@@ -87,7 +87,15 @@ export const getRailpackCommand = (application: ApplicationNested) => {
 # Ensure we have a builder with containerd (isolated per build)
 
 export RAILPACK_VERSION=${application.railpackVersion}
-bash -c "$(curl -fsSL https://railpack.com/install.sh)"
+# use sudo for non-root so the install can write to /usr/local/bin
+if [ "$(id -u)" -eq 0 ]; then
+	SUDO_CMD=""
+elif sudo -n true 2>/dev/null; then
+	SUDO_CMD="sudo"
+else
+	SUDO_CMD=""
+fi
+$SUDO_CMD bash -c "$(curl -fsSL https://railpack.com/install.sh)"
 docker buildx create --name ${builderName} --driver docker-container || true
 
 echo "Preparing Railpack build plan..." ;