RemoteScenePickerActivity

Standalone activity wrapping fixo::ScenePickerWidget.

Detailed description

Mounts the published-spec scene picker as a navigable Remote activity. The widget subscribes to the Agent's `fixo-runtime` section through the Remote's `ConfigSyncService`; clicking a scene button writes the corresponding `applyTrigger` monotonic counter, which the Agent's `RuntimeCourier` picks up and routes through `Runtime::applyScene`. `lastAppliedScene` drives the active- scene highlight on whichever button is currently the authoritative-applied scene.