Dockerfile copies nuget.config (so the Gitea feed + source mapping are known in
the restore stage) and accepts optional NUGET_GITEA_USER/PASS build-args for a
private feed; build.sh forwards them from host env vars (MXGW_NUGET_USER/PASS)
so secrets are never committed. Verified the in-container restore resolves the
ZB.MOM.WW.MxGateway.* packages (anonymous feed).
Multi-stage Dockerfile with NuGet restore layer caching, per-node appsettings
with Docker hostnames, shared bridge network with infra services, and
build/deploy/teardown scripts. Ports use 90xx block to avoid conflicts.