Gateway source moved out of src/ subdirectory but Dockerfile still
referenced old paths, breaking docker build. Rewrite to use tsx runtime
(no tsc/esbuild compile step), copy all workspace package.json for
lockfile compatibility, and filter install to gateway deps only (616 vs
1911 packages). Also update build-and-push script to tag latest.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>