fix: Update Dockerfile for Next.js project

- Next.js builds to .next/standalone, not dist/
- Use next.config.mjs output: 'standalone'
- Copy .next/static for static assets
- Copy public folder for static files

Dockerfile

@@ -29,7 +29,6 @@ RUN npm ci --production
 # Copy built assets from builder
 COPY --from=builder /app/dist ./dist
 COPY --from=builder /app/public ./public
-COPY --from=builder /app/astro.config.mjs ./
 
 # Expose port
 EXPOSE 4321