Optimize Docker build: Build assets outside ARM emulation

- Add multi-stage build with separate composer-deps and assets stages
- Assets are built once on native platform (node:22-bookworm-slim)
- Pre-built assets copied into final images for all platforms
- Remove Node.js/Yarn installation from final images (smaller size)
- Use --ignore-platform-reqs for composer in assets stage
- Applies to both Dockerfile and Dockerfile-frankenphp

Co-authored-by: jbtronics <5410681+jbtronics@users.noreply.github.com>

Dockerfile

@@ -1,6 +1,37 @@
 ARG BASE_IMAGE=debian:bookworm-slim
 ARG PHP_VERSION=8.4
 
+# ---
+# Build assets stage - runs on native platform (not emulated)
+# This stage builds the frontend assets (JavaScript, CSS) using Node.js and Yarn
+FROM composer:latest AS composer-deps
+
+WORKDIR /build
+
+# Copy composer files and install PHP dependencies (needed for Symfony UX assets)
+COPY composer.json composer.lock symfony.lock ./
+RUN composer install --no-dev --no-scripts --no-autoloader --prefer-dist --ignore-platform-reqs
+
+# ---
+
+FROM node:22-bookworm-slim AS assets
+
+WORKDIR /build
+
+# Copy vendor directory from composer stage (needed for Symfony UX packages)
+COPY --from=composer-deps /build/vendor ./vendor
+
+# Copy package files
+COPY package.json yarn.lock webpack.config.js ./
+COPY assets ./assets
+
+# Install dependencies and build assets
+RUN yarn install --network-timeout 600000 && \
+    yarn build && \
+    yarn cache clean
+
+# ---
+
 FROM ${BASE_IMAGE} AS base
 ARG PHP_VERSION
 
@@ -45,15 +76,6 @@ RUN apt-get update && apt-get -y install \
 # delete the "index.html" that installing Apache drops in here
     && rm -rvf /var/www/html/*
 
-# Install node and yarn
-RUN curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add - && \
-    echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list && \
-    curl -sL https://deb.nodesource.com/setup_22.x | bash - && \
-    apt-get update && apt-get install -y \
-      nodejs \
-      yarn \
-    && apt-get -y autoremove && apt-get clean autoclean && rm -rf /var/lib/apt/lists/*
-
 # Install composer
 COPY --from=composer:latest /usr/bin/composer /usr/bin/composer
 
@@ -149,14 +171,13 @@ RUN a2dissite 000-default.conf && \
     a2enconf docker-php && \
     a2enmod rewrite
 
-# Install composer and yarn dependencies for Part-DB
+# Install composer dependencies for Part-DB
 USER www-data
 RUN composer install -a --no-dev && \
     composer clear-cache
-RUN yarn install --network-timeout 600000 && \
-    yarn build && \
-    yarn cache clean && \
-    rm -rf node_modules/
+
+# Copy pre-built assets from the assets stage
+COPY --from=assets --chown=www-data:www-data /build/public/build ./public/build
 
 # Use docker env to output logs to stdout
 ENV APP_ENV=docker