Skill follow-up: scoped-colocation

## Summary
Address the follow-up actions for the scoped-colocation skill as identified in the skills review.

## Acceptance Criteria
- [ ] Add sample directory layouts and a simple audit checklist.

## Scope
- Applies to `skills/scoped-colocation/`
- Derived from skills-review.md (commit 9c59dbc)

## Parent
- Refs: #297
