blueprint

# blueprint — Full-Product Blueprint (Flow-First) Maintain the **whole product's** desired end state under `docs/blueprint/`. The blueprint is product-wide and permanent — not feature-specific. It is organized by **process**: the primary unit is the **flow** (a user or system journey to an observable outcome), and flows are the goal-traceability spine — product goal → flow → the entities, API operations, screens, and jobs the flow needs. Entities are **supporting data contracts** the flows stand on. The doc units: - **Flow** — `docs/blueprint/flows/<project>/<device>/<NNN>-<flow>/index.md` for a UI project's flows, `docs/blueprint/flows/<project>/<NNN>-<flow>/index.md` for a non-UI project's (always `index.md` only; a flow too big for one file is several flows). Flows are **grouped by their primary registry project** — the project that owns the journey (the UI project of its Screens; for a UI-less flow, the service/worker whose trigger starts it; ambiguous → ask, never guess) — then, for UI projects, by **device-type subgroup**: the project's primary surface (`mobile` for `frontend`, `web` for `site`/`console`) plus one subgroup per declared in-car platform (`carplay`, `android-auto`), whose journeys are their **own subset flows** (§2 Automotive). Within a subgroup (or a non-UI project group) flows are **numbered in execution order** (`010-splash`, `020-signin`, …): three digits, **gap numbering** in steps of 10 so an insert takes a number between i...