issues/27: docker build webpack assets in image

Dockerfile

@@ -1,5 +1,14 @@
 # syntax=docker/dockerfile:1
 
+FROM node:24-alpine AS assets
+WORKDIR /app
+COPY package.json yarn.lock ./
+RUN corepack enable && yarn install --frozen-lockfile
+COPY webpack.config.js ./
+COPY assets ./assets
+COPY public ./public
+RUN yarn build
+
 FROM composer:2 AS vendor
 WORKDIR /app
 COPY composer.json composer.lock* ./
@@ -29,6 +38,7 @@ RUN cp /usr/share/zoneinfo/$TZ /etc/localtime && echo "$TZ" > /etc/timezone
 
 COPY docker/fpm-pool.conf /usr/local/etc/php-fpm.d/zz-docker.conf
 COPY --from=vendor /app /app
+COPY --from=assets /app/public/build /app/public/build
 
 RUN mkdir -p var/cache var/log public/uploads public/banners \
     && chown -R www-data:www-data var public/uploads public/banners \