Support sub-folders and additional arbitrary files in a skill

[SecKatie]

I would like to be able to include arbitrary additional content like scripts, templates, and references in my skills.

AgentSkills.io describes this format:

my-skill/
├── SKILL.md          # Required: metadata + instructions
├── scripts/          # Optional: executable code
├── references/       # Optional: documentation
├── assets/           # Optional: templates, resources
└── ...               # Any additional files or directories

Is it possible to use this in skillimage? I didn't see an example with anything other than the SkillCard yaml and the SKILL.md.

[SecKatie]

Would the maintainers be open to a PR that adds support for this in the spec?