Decouple the reveal logic from the `Article` component by introducing
a `RevealManager` component and an `ArticleDomCtx`. This allows the
reveal logic to reactively manage DOM injections and classes without
polluting the `Article` component's props or lifecycle.
Additionally, implements a robust `cleanupInjections` mechanism to
ensure that injected buttons and styling artifacts are properly removed
during navigation, role changes, or disconnections.
