Agent Skills: rtvi-cv-scaffold-vss-service declares compatibility inside metadata

While reviewing the skills in this repository against the Agent Skills specification, I found that skills/rtvi-cv-scaffold-vss-service/SKILL.md declares its compatibility field nested inside metadata instead of at the top level. Spec-conformant harnesses read the top-level compatibility field, so the requirements (Python 3.10+, VSS deployment prerequisites) are effectively invisible to them.

Fix available at https://github.com/janEbert/DeepStream/tree/fix-agent-skills.