fix(docs): add docker.io prefix for podman compatibility (#1030)

Fixes #1013

- Add docker.io/ prefix to Docker image names for podman-docker compatibility
- Add mkdir -p command to create .config/croc directory before mounting

This ensures the Docker commands work correctly with:
- podman-docker on Ubuntu 24.04+
- Any system with unqualified-search registries disabled

Co-authored-by: Murat Aslan <murataslan1@users.noreply.github.com>