Feature flow specs and shared conventions for the starter projects. Everything here is implementation-agnostic, so a Stripe subscription flow reads the same whether it lands in Laravel, Rails, Django, Vue, React, or mobile. Only the library choices differ, and those are a code session problem.
Each feature gets one flow file holding a description, the shared terms, the requirements, the numbered steps, a mermaid diagram, notes, and outstanding items. Anything that isn't a feature gets a plain doc with no fixed structure. Every term used in either is defined once and copied word for word wherever it appears, so the same word never means two things across the API and the app.
The flows are the contract both sides build against. The API implements its half, the app implements its half, and neither has to guess what the other assumes.
Flows, refs, and conventions live in starter-flows, with a markdown viewer for reading them locally.