v1.1: Add CIDR subnet filtering and Agent filter in Devices page

backend/Dockerfile

@@ -0,0 +1,20 @@
+FROM node:18-alpine
+
+# Create app directory
+WORKDIR /app
+
+# Install dependencies first (layer caching)
+COPY package*.json ./
+RUN npm install --omit=dev
+
+# Copy application source
+COPY . .
+
+# Expose backend API port
+EXPOSE 3001
+
+# Health check
+HEALTHCHECK --interval=30s --timeout=10s --start-period=20s --retries=3 \
+  CMD node -e "require('http').get('http://localhost:3001/api/health', r => r.statusCode === 200 ? process.exit(0) : process.exit(1)).on('error', () => process.exit(1))"
+
+CMD ["node", "server.js"]