Update Dockerfile to use Node.js 20 for Next.js 16 compatibility

Dockerfile

@@ -1,5 +1,5 @@
-# Use Node.js 18 Alpine for smaller image size
-FROM node:18-alpine AS base
+# Use Node.js 20 Alpine for smaller image size
+FROM node:20-alpine AS base
 
 # Install dependencies only when needed
 FROM base AS deps