flutter-conventions-indexlisted

# Flutter Conventions — Index The front door for this Flutter/Dart app. It states the cross-cutting **house rules** every task obeys, then **routes each concern to a focused skill**. For any non-trivial task: apply the rules here, then open the specialized skill for depth. This is the only skill that names every other skill in the library. Assumes a **single-package Flutter app** by default. Monorepo / pub-workspace guidance is fenced inside the skills that own it (`project-structure-and-packages`, `codegen-and-toolchain`) — never required for a small app. ## Non-negotiable rules 1. **Feature-first, layered, downward-only.** Group by feature (a folder), then by layer: View → ViewModel → Repository → Service/data. Lower layers never import upward; the dependency graph is a strict DAG. WHY: an acyclic downward graph is the only structural guard against a big ball of mud. *(`flutter-architecture`, `project-structure-and-packages`)* 2. **Widgets are dumb.** No business logic, data access, math, or formatting in a widget — it reads state and renders. WHY: logic in `build()` is untestable and rebuilds unpredictably. *(`widget-composition`)* 3. **One ViewModel per screen, over immutable state.** A single `Notifier`/`AsyncNotifier` owns private mutable state and exposes it as an immutable value with value equality; a transition assigns a new state, never mutates in place. WHY: immutable value + single owner makes every change diffable and testable. *(`state-management-riverpod`)*