huskies: merge 1107 story Chat bootstrap Phase 2a: stack-overlay framework + Rust and Node stack overlays

docker/stacks/node/Dockerfile.fragment

@@ -0,0 +1,26 @@
+# Node stack overlay fragment.
+#
+# Layer this on top of huskies-project-base to produce a project container
+# with Node.js 22, TypeScript (tsc), and typescript-language-server.
+#
+# Build the combined image:
+#   (echo "FROM huskies-project-base"; \
+#    cat docker/stacks/node/Dockerfile.fragment) | \
+#   docker build -t huskies-project-node -
+#
+# Adding a new stack: create docker/stacks/<name>/Dockerfile.fragment and
+# docker/stacks/<name>/markers — no changes to orchestration code required.
+
+USER root
+
+# Node.js 22.x (LTS).
+RUN curl -fsSL https://deb.nodesource.com/setup_22.x | bash - \
+    && apt-get install -y --no-install-recommends nodejs \
+    && rm -rf /var/lib/apt/lists/*
+
+# TypeScript compiler and language server for LSP-aware agents.
+# tsc:                       TypeScript compiler (tsc --version)
+# typescript-language-server: LSP server used by editors/agents
+RUN npm install -g typescript typescript-language-server
+
+USER huskies