Add color variants to label component

Editor assessment

The subject states a concrete addition, color variants for the label component, and chore is a loose type for a visible component capability where feat or style fits better, though the straddle is arguable. The body's bullets add one real fact, the component moved to the UI folder, but never explain which variants exist or how they are applied. No scope, no footers. The trailing pull-request number is conventional. Hygiene is otherwise fine. Understandable and valid, with the variant list left unwritten.