juanjoDiaz/serverless-plugin-warmup — reverse-engineered prompt

Build me a JavaScript plugin for the Serverless Framework that helps reduce AWS Lambda cold starts. I want it to add a scheduled warmer Lambda to a service, then have that warmer call the selected functions every few minutes so their containers stay warm.

It should be configurable from serverless.yaml under custom warmup. Let people create one or more warmers, turn them on or off by stage, choose the schedule, concurrency, payload, memory, timeout, VPC, tags, logging, tracing, and whether to run once right after deployment. Each function should also be able to override whether it uses a warmer.

Please make sensible defaults, create only the needed IAM permissions, generate any temporary warmer code during packaging, and clean it up unless configured otherwise. Include useful errors for bad config and tests for the main behavior. Look up current Serverless Framework and AWS Lambda docs online if you need to.