build: add production frontend images

docker/Dockerfile.admin

@@ -0,0 +1,19 @@
+# syntax=docker/dockerfile:1
+
+FROM node:20-alpine AS build
+
+WORKDIR /app
+
+COPY package.json package-lock.json ./
+RUN npm ci --no-audit --no-fund
+
+COPY . .
+
+ARG VITE_APP_BASE_URL=https://api.sbnews.net
+ENV VITE_APP_BASE_URL=${VITE_APP_BASE_URL}
+
+RUN npx vite build
+
+FROM registry.cn-guangzhou.aliyuncs.com/likeadmin/nginx:1.23.1
+
+COPY --from=build /app/dist/ /usr/share/nginx/html/