Add Dockerfile for standalone deployment

Dockerfile

@@ -0,0 +1,20 @@
+FROM node:20-alpine
+
+ENV NODE_ENV=production \
+    NEXT_TELEMETRY_DISABLED=1 \
+    HOST=0.0.0.0 \
+    PORT=7860
+
+WORKDIR /app
+
+# Copy package.json and install production dependencies
+COPY package.json ./
+RUN npm install --only=production
+
+# Copy standalone server and build artifacts
+COPY server.js .
+COPY .next ./.next
+COPY public ./public
+
+EXPOSE 7860
+CMD ["node", "server.js"]