huskies: merge 1110 story Chat bootstrap Phase 2b: additional stack overlays (Go, Python, Ruby, JVM)

docker/stacks/go/Dockerfile.fragment

@@ -0,0 +1,28 @@
+# Go stack overlay fragment.
+#
+# Layer this on top of huskies-project-base to produce a project container
+# with Go 1.22, gopls (official Go language server), and standard tooling.
+#
+# Build the combined image:
+#   (echo "FROM huskies-project-base"; \
+#    cat docker/stacks/go/Dockerfile.fragment) | \
+#   docker build -t huskies-project-go -
+#
+# Adding a new stack: create docker/stacks/<name>/Dockerfile.fragment and
+# docker/stacks/<name>/markers — no changes to orchestration code required.
+
+USER root
+
+# Official Go binary distribution — Debian's golang-go package is too old for gopls.
+# Update GOVERSION to pick up a newer release.
+ENV GOVERSION="1.22.3"
+RUN curl -fsSL "https://go.dev/dl/go${GOVERSION}.linux-amd64.tar.gz" \
+        | tar -C /usr/local -xzf -
+
+ENV PATH="/usr/local/go/bin:${PATH}"
+
+# gopls: the official Go language server.
+# GOBIN=/usr/local/bin puts the binary on the system PATH for all users.
+RUN GOBIN=/usr/local/bin go install golang.org/x/tools/gopls@latest
+
+USER huskies