Add the build script used to run the bundler with Node 22

/usr/bin/node is v18 here and too old for the toolchain, so every build has to
prepend /opt/node22/bin. The script also sets pipefail, since piping npm output
otherwise reports tail's exit code.

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

build.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+set -o pipefail && PATH=/opt/node22/bin:$PATH npm run build