Add Containerfile for production use

Signed-off-by: Asai Neko <sugar@sne.moe>

Containerfile

@@ -0,0 +1,27 @@
+FROM docker.io/node:22-alpine AS client-build
+RUN npm install -g corepack && \
+    corepack enable
+WORKDIR /app
+ENV VITE_APP_BASE_URL=$CLIENT_BASE_URL
+COPY . .
+RUN cd /app/client && \
+    pnpm install -r --frozen-lockfile && \
+    pnpm run build
+
+FROM docker.io/busybox:1.37 AS client
+WORKDIR /app
+COPY --from=client-build /app/client/dist .
+EXPOSE 3000
+ENTRYPOINT ["httpd", "-f", "-p", "3000", "-h", "/app", "-v"]
+
+FROM docker.io/golang:1.25.5-alpine AS backend-build
+WORKDIR /app
+COPY . /app
+RUN go mod tidy && \
+    go build -o /app/nixcn-cms
+
+FROM docker.io/alpine:3.23 AS backend
+WORKDIR /app
+COPY --from=backend-build /app/nixcn-cms /app/nixcn-cms
+EXPOSE 8000
+ENTRYPOINT [ "/app/nixcn-cms" ]