seed: devroadmap-demo — self-hosted CI loop

Dockerfile

@@ -0,0 +1,17 @@
+# Trimmed devroadmap demo — a static landing served by nginx. Deliberately light
+# so the arm64 in-cluster build is fast/reliable (the demo is the CI/CD LOOP, not
+# a heavy build). Swap in the full Astro SSR build (node:22-alpine + pnpm, RU npm
+# mirror registry.npmmirror.com) later — the pipeline stays identical.
+FROM docker.io/library/nginx:1.27-alpine
+
+ARG GIT_SHA=dev
+ARG BUILD_DATE=unknown
+
+COPY site/ /usr/share/nginx/html/
+
+# "build" step: stamp the commit + date into the page so every deploy is visibly
+# different — proves the loop end-to-end from the browser.
+RUN sed -i "s/__GIT_SHA__/${GIT_SHA}/g; s/__BUILD_DATE__/${BUILD_DATE}/g" \
+      /usr/share/nginx/html/index.html
+
+EXPOSE 80