Expand Spec Product

Create a PRODUCT spec — the non-technical document that comes FIRST, before any architecture or technical spec. Use when the user has a product idea, problem, or rough notes and wants a thought-through product spec: the gap, why it matters, who it's for, the proposed solution, the phasing, the user journeys, and the risks — written for humans to decide and align on. This is the upstream of /expand-spec-architecture, /expand-spec-technical and /build-plan: the product spec defines WHAT and WHY; those downstream skills define HOW. Do not reverse the order — a product spec reverse-engineered from a tech spec is a rationalisation, not a product decision. The defining move o…