Scaffold a feature module

Stand up one feature the same way every time: a folder lib/features/<feature>/ whose presentation/ holds a dumb View, its 1:1 Notifier/AsyncNotifier ViewModel, leaf widgets/, and scoped providers (feature-local models live in an optional domain/). A feature is a folder, not a package. It reads shared repositories from lib/data/ and shared foundation from lib/core/, routes every write through them, and depends only downward — never sideways into another feature. (The single-package tree is owned by project-structure-and-packages.)

Agnostic core (holds under any state library): the View is dumb; one ViewModel per feature owns private mutable state and exposes intent methods that assign a new immutable value; reads derive from the repository (the single source of truth), writes go through one repository method (the single write path, persist-before-publish); the feature depends on abstractions and navigates by route ID. The Riverpod-first "how" below wires that with Notifiers, scoped StreamProviders, and providers-as-DI.

Read the reference for the task at hand:

• references/anatomy-and-wiring.md — the fixed folder shape, the Notifier + scoped stream, watch/read/listen, family+autoDispose vs keepAlive, the single write path, and the ViewModel test.
• references/routing-and-l10n.md — typed go_router registration (path params, not state.extra) and the ARB parity workflow.
• references/add-persisted-record.md — the optional model → table → DAO → repository chain when the feature reads a brand-new record (defers to persistence-drift).