fix: ensure public dir exists in build, fix serverExternalPackages for Next.js 14

Dockerfile

@@ -3,6 +3,7 @@ WORKDIR /app
 COPY package*.json ./
 RUN npm ci
 COPY . .
+RUN mkdir -p public
 RUN npm run build
 
 FROM node:20-alpine AS runner

next.config.js

@@ -1,7 +1,9 @@
 /** @type {import("next").NextConfig} */
 const nextConfig = {
   output: "standalone",
-  serverExternalPackages: ["@kubernetes/client-node"],
+  experimental: {
+    serverComponentsExternalPackages: ["@kubernetes/client-node"],
+  },
 };
 
 module.exports = nextConfig;