fixed frontend build

frontend/Dockerfile.prod

@@ -13,8 +13,26 @@ RUN echo "date.timezone = Europe/Berlin" > $PHP_INI_DIR/conf.d/timezone.ini
 
 WORKDIR /app
 COPY . .
-RUN composer install --no-interaction --no-dev --optimize-autoloader \
-    && php bin/console cache:clear --env=prod --no-debug
+
+# Symfony's dotenv bootstrap (SymfonyRuntime) unconditionally looks for
+# .env/.env.dist on every boot. Real config (DATABASE_URL etc.) is injected
+# as actual container env vars at runtime instead (see docker-compose.yaml's
+# env_file), which doesn't exist yet at build time — an empty placeholder
+# just satisfies dotenv's file-exists check; real env vars always take
+# precedence over anything (not) found in it.
+RUN touch .env \
+    && composer install --no-interaction --no-dev --optimize-autoloader
+
+# cache:clear needs real config (DATABASE_URL) to compile the container, so
+# it can't run here at build time — it runs at container start instead, via
+# this entrypoint, once env_file has actually been applied.
+COPY docker-entrypoint.prod.sh /usr/local/bin/docker-entrypoint.prod.sh
+RUN chmod +x /usr/local/bin/docker-entrypoint.prod.sh
+ENTRYPOINT ["docker-entrypoint.prod.sh"]
+# Docker resets CMD to empty whenever a Dockerfile sets a new ENTRYPOINT,
+# even without touching CMD — restate the base image's own default here or
+# the wrapper above execs with no arguments and FrankenPHP never starts.
+CMD ["--config", "/etc/frankenphp/Caddyfile", "--adapter", "caddyfile"]
 
 # Caddy's default site address in the base image's Caddyfile is
 # {$SERVER_NAME:localhost}; a bare ":8000" (no hostname) makes it listen