Implement wiring hardening, runtime API config, smoke tests, and build scripts

backend/Dockerfile

@@ -1,12 +1,20 @@
 FROM node:20-alpine
 
+ENV NODE_ENV=production
+
 WORKDIR /app
 
 COPY package*.json ./
-RUN npm install --omit=dev
+RUN apk add --no-cache curl && npm install --omit=dev
 
 COPY . .
+RUN chown -R node:node /app
+
+USER node
 
 EXPOSE 4000
 
+HEALTHCHECK --interval=30s --timeout=5s --start-period=5s --retries=3 \
+	CMD curl -f http://localhost:4000/health || exit 1
+
 CMD ["node", "index.js"]