Features register through a function over a context

An editor registers from many features: the brush today, later layers, templates and world commands. Wired into the boot class by hand, every feature would add a field, a call and a teardown line there.

A feature is instead a ConsoleFeature<TContext>, a function from the console and a context to a handle. The editor keeps one list and calls registerConsoleFeatures once. The returned handle unregisters every feature in reverse order, and a feature that throws while registering rolls back the ones before it.

Each feature types its context as the slice it reads, such as Pick<VoxelMapWorkspace, "state">, so its spec builds that slice alone while the editor passes the whole workspace.

Considered Options

• A method on CommandConsole, like commands.registerFeatures(). It behaves the same and ties the class to a list shape it has no other use for.
• Living in editor.host. The pixel-art library declares its keybind feature without depending on the host, and nothing in the contract is specific to editors.

Consequences

One namespace per feature. Registering a namespace name again replaces it whole (ADR-0003), so two features sharing brush would drop each other's entries.