… is disabled

Realized we can use listener middleware to respond to _actions_, as opposed to using the redux store subscription to respond to _state changes_... This might simplify some things.

Using this pattern here.

Only hiccup - there's a TS issue preventing this from being added to the state api module. The `addListener` method has an overloaded type signature and TS cannot extract the overloaded arg type using `Parameters<T>`. As a result, if we try to wrap this, we end up with a broken TS signature for the wrapper method.

Snap can be any of off, 8px or 64px.

The snap is used when moving and transforming entities.

When transforming and locking aspect ratio, the snap is ignored entirely, because we'd change the aspect ratio if we forced the snap.

Otherwise, if we are not locking aspect ratio (e.g. the user is holding shift), we snap the transform anchors to the grid.