plan-feature-decisionlisted

# Plan-feature: gstack-decision — STUB Phase 3.2 D-03 WIRED reference implementation. Returns mock decision output for workflow runtime verification. ## Stub behavior This skill stub returns a mock result to simulate phase success transition: ```json { "status": "ok", "output": "<stub for plan-feature-decision>", "decision": "mock-approved" } ``` Phase 3.3+ dogfood: replace stub with actual `{{ gstack_prefix }}office-hours` spawn + decision capture.