fix: upgrade Dockerfile to Node.js 20 for Next.js build

Dockerfile.backup

@@ -0,0 +1,26 @@
+FROM node:18-alpine AS builder
+
+WORKDIR /app
+
+COPY package*.json ./
+RUN npm install
+
+COPY . .
+
+RUN npm run build
+
+FROM node:18-alpine AS runner
+
+WORKDIR /app
+
+COPY --from=builder /app/.next ./.next
+COPY --from=builder /app/public ./public
+COPY --from=builder /app/package*.json ./
+COPY --from=builder /app/node_modules ./node_modules
+
+ENV NODE_ENV=production
+ENV HOST=0.0.0.0
+
+EXPOSE 3000
+
+CMD ["npm", "start"]