Construct a skill instance from the provided class and add it via
addSkill. Catches any throw from addSkill and returns a
[success, errorMessage] tuple — matching the Python SDK’s load_skill
return contract.
A concrete subclass of SkillBase.
Optional configuration forwarded to the skill constructor.
Promise<[boolean, string]> — [true, ''] on success, [false, errorMessage]
on any validation or setup failure.