mobiler-ui 0.4.0

Mobiler's fixed UI wire ABI.

These types are the stable contract between any Mobiler app's Rust core and the native shell. Because they never change per app, a single shell is built once and renders any Mobiler app — the shell only ever knows these types, never an app's domain events or widgets.

• The core emits a [Widget] tree (the ViewModel).
• The shell sends back an [Action] (the Event).
• App domain events ride inside actions as opaque [ActionToken]s that the shell round-trips without interpreting.

Style is expressed as intent tokens (e.g. [TextStyle], [Tone]); the shell maps each to a concrete look (font, color, dp), so dark mode and theme come for free on the native side.