fix: simpler Dockerfile without standalone mode

Dockerfile

@@ -1,20 +1,10 @@
-FROM node:22-alpine AS deps
+FROM node:22-alpine
 WORKDIR /app
+ENV NODE_ENV=production
+ENV PORT=4028
 COPY package*.json ./
 RUN npm ci
-
-FROM node:22-alpine AS builder
-WORKDIR /app
-COPY --from=deps /app/node_modules ./node_modules
 COPY . .
 RUN npm run build
-
-FROM node:22-alpine AS runner
-WORKDIR /app
-ENV NODE_ENV production
-ENV PORT 4028
-COPY --from=builder /app/.next/standalone ./
-COPY --from=builder /app/.next/static ./.next/static
-COPY --from=builder /app/public ./public
 EXPOSE 4028
-CMD ["node", "server.js"]
+CMD ["npx", "next", "start", "-p", "4028"]