Skill follow-up: runtime-tooling-validation

## Summary
Address the follow-up actions for the runtime-tooling-validation skill as identified in the skills review.

## Acceptance Criteria
- [ ] Add command-output examples and a minimal ÔÇ£must-passÔÇØ checklist by stack.

## Scope
- Applies to `skills/runtime-tooling-validation/`
- Derived from skills-review.md (commit 9c59dbc)

## Parent
- Refs: #297
