chore: import upstream snapshot with attribution

showcase/integrations/ms-agent-dotnet/Dockerfile

@@ -0,0 +1,71 @@
+# Stage 1: Build Next.js frontend
+FROM node:22-slim AS frontend
+WORKDIR /app
+COPY package.json package-lock.json ./
+RUN npm ci --legacy-peer-deps
+COPY . .
+RUN npm run build
+
+# Stage 2: Build .NET agent
+FROM mcr.microsoft.com/dotnet/sdk:9.0.312 AS agent-build
+WORKDIR /agent
+COPY agent/ ./
+# CVDIAG shared binding (plan unit L1-F): the single-source emitter lives at
+# showcase/integrations/_shared/dotnet/ and is source-included by the csproj via
+# ..\_shared\dotnet\*.cs. The `_shared` symlink at this integration's root is
+# materialized to a real dir by the harness stage_shared step, so it is present
+# in the build context here. Land it at /_shared/dotnet so the csproj at /agent
+# resolves ..\_shared\dotnet (= /_shared/dotnet) identically to the local layout.
+COPY _shared/dotnet/*.cs /_shared/dotnet/
+# Explicit project path: the tests/ subdirectory contains a separate test csproj
+# that must not be picked up by the default glob when publishing the web agent.
+RUN dotnet publish ProverbsAgent.csproj -c Release -o /agent/publish
+
+# Stage 3: Production image — aspnet runtime + Node.js (no SDK, no build tools)
+FROM mcr.microsoft.com/dotnet/aspnet:9.0.14 AS runner
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    curl && \
+    curl -fsSL https://deb.nodesource.com/setup_22.x | bash - && \
+    apt-get install -y nodejs && \
+    apt-get clean && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+# Create unprivileged runtime user BEFORE any COPY so --chown resolves
+# by name and so recursive chown over /app is never needed (fast builds).
+RUN (groupadd --system --gid 1001 app 2>/dev/null || true) \
+ && (useradd --system --uid 1001 --gid 1001 --no-create-home app 2>/dev/null || true) \
+ && mkdir -p /home/app && chown app:app /home/app
+
+# Next.js build artifacts (from frontend stage — no npm install at runtime)
+COPY --chown=app:app --from=frontend /app/.next ./.next
+COPY --chown=app:app --from=frontend /app/node_modules ./node_modules
+COPY --chown=app:app --from=frontend /app/package.json ./
+COPY --chown=app:app --from=frontend /app/public ./public
+
+# .NET agent binary (from agent-build stage — no dotnet SDK at runtime)
+COPY --chown=app:app --from=agent-build /agent/publish /agent
+
+# Entrypoint
+COPY --chown=app:app entrypoint.sh ./
+RUN chmod +x entrypoint.sh
+
+# Ensure WORKDIR itself is owned by `app` — `WORKDIR /app` at the top of the
+# stage creates /app as root, and `COPY --chown=app:app` only reassigns the
+# copied files, NOT the parent dir. Without this, any subprocess that tries
+# to mkdir under /app at runtime (Next.js build caches, .NET tooling
+# caches, etc.) hits EACCES under the unprivileged user and crashes the
+# container.
+RUN chown app:app /app
+# Ensure /agent is traversable by the app user (dotnet reads from here).
+RUN chown -R app:app /agent
+USER app
+
+EXPOSE 10000
+# Intentionally NOT setting `ENV NODE_ENV=production` at the image level.
+# entrypoint.sh scopes NODE_ENV=production to the Next.js invocation only
+# so non-Next children (dotnet agent, shell, healthchecks) see the host's
+# environment.
+ENV PORT=10000
+ENV HOSTNAME=0.0.0.0
+CMD ["./entrypoint.sh"]