fix: Update to use x.y.z-buildid format for base image tags and return 0 for usage

[josephca]

• Update to use 'x.y(.z)-buildid' format for base image tags. The related change can be found at https://redhat.atlassian.net/browse/RHIDP-14725
• fixed: usage() in analyze-base-images.sh calls exit 1, so --help returns a failure code. Convention is exit 0 for help requests return 0 (a follow-up from feat: add update-base-image skill #39)

Assisted-by: Cursor