build: add Docker deployment

Created a Dockerfile and nginx configuration and added environment
variables into the codebase to support Docker compose.

ref: N25B-282

Dockerfile

@@ -0,0 +1,46 @@
+# --- Building static files ---
+FROM node:23-alpine AS build
+
+WORKDIR /app
+
+COPY package.json package-lock.json ./
+
+RUN npm ci
+
+COPY . .
+
+RUN npm run build
+
+
+# --- Serving ---
+FROM nginx:alpine
+
+RUN mkdir -p /app/www
+
+COPY --from=build /app/dist /app/www
+
+COPY nginx.conf /etc/nginx/templates/default.conf.template
+
+RUN adduser -D -H -u 1001 -s /sbin/nologin webuser
+
+RUN chown -R webuser:webuser /app/www && \
+  chmod -R 755 /app/www && \
+  chown -R webuser:webuser /var/cache/nginx && \
+  chown -R webuser:webuser /var/log/nginx && \
+  chown -R webuser:webuser /etc/nginx/conf.d && \
+  touch /var/run/nginx.pid && \
+  chown -R webuser:webuser /var/run/nginx.pid && \
+  chmod -R 777 /etc/nginx/conf.d
+
+ENV PORT=80
+ENV NGINX_ENVSUBST_TEMPLATE_DIR=/etc/nginx/templates
+ENV NGINX_ENVSUBST_TEMPLATE_SUFFIX=.template
+ENV NGINX_ENVSUBST_OUTPUT_DIR=/etc/nginx/conf.d
+# Default value, potentially overwritten in compose file
+ENV BACKEND_ADDRESS="http://localhost:8000"
+
+EXPOSE ${PORT}
+
+USER webuser
+
+CMD [ "nginx", "-g", "daemon off;" ]