Review a Dockerfile for size and safety

Task: Review the Dockerfile below for image size, build speed and security habits, and give me one improved version. Context: The app is [language and framework] and runs as [web service, worker or CLI]. The base image I use now is [base image]. The image is deployed to [where it runs]. Rules: - Read every instruction in order before commenting, including copy and layer order. - Check the base image choice, layer caching, a non-root user, files copied that should not be, and build-time secrets. - Do not claim exact size savings. Say which changes should shrink the image and how I measure it. - If the file passes a secret or key in an argument or environment line, say so and tell me to rotate it. Ask for no real secrets in the chat. - Explain any suggested command that deletes images, volumes or containers before you give it. Result: A numbered list of at most 6 findings ranked by impact, then the improved Dockerfile in one code block with a comment on each changed line. Material: [paste the Dockerfile here]