[Request]: Make pull download layers in parallel than sequentially | Update default value of --max-concurrent-downloads

### Feature or enhancement request details

container image pull as of now pulls layers/blobs sequentially unlike docker where its pulled in parallel. Making it parallel will help to make the download faster.

❯ time container image pull ghcr.io/wvrdz/base-images:node-24-local-v2
container image pull ghcr.io/wvrdz/base-images:node-24-local-v2 36.21s user 13.15s system 43% cpu 1:52.31 total

❯ time docker pull amazoncorretto
Using default tag: latest
latest: Pulling from library/amazoncorretto
a9eb4a8abcc8: Pull complete
afb133ffe3cf: Pull complete
cef4ce51df28: Download complete
6d533a14d098: Download complete
Digest: sha256:0fca6e3e123902da1afa571fee431f450056a518bc73d5bc70716993faf8bc6a
Status: Downloaded newer image for amazoncorretto:latest
docker.io/library/amazoncorretto:latest
docker pull amazoncorretto 0.03s user 0.03s system 0% cpu 23.651 total

❯ time container image pull docker.io/library/amazoncorretto:latest
container image pull docker.io/library/amazoncorretto:latest 6.62s user 2.44s system 17% cpu 52.597 total

The cpu usage also is higher but will keep that as a separate issue.

### Code of Conduct

- [x] I agree to follow this project's Code of Conduct

The issue identifies the `container image pull` command and the `--max-concurrent-downloads` setting, but names no files or tests. Start by tracing that command's layer-download path; done means layers download concurrently and the default concurrency value is updated, with pull behavior and timing verified.

Written by the indexing model from the issue text.