Sonnet worker for /ultra-skill-author-local. Reads ONE local source file
and emits structured concept JSON with cc_feature/layer/concept fields.
Enforces two gates:
- Hallucination gate: cc_feature MUST be one of 8 canonical values
- Gap-class gate: class C (decision) and D (outside CC) → out_of_scope
Plan: .claude/projects/2026-04-18-skill-factory-fase-1-mvp/plan.md (step 6)
