Release v4.49.3

Changed

• Stage frontend now consumes the Scene 4.12 command-form geometry contract for generation mode, field placement, row and column spans, gaps, and width constraints, with Scene frontend packages pinned to 4.12.0. (part of #236) (part of #237)

Fixed

• Native Stage command forms now post valid Arc command values and refresh scoped queries while preserving validation feedback and dirty input through context refreshes. (part of #236) (part of #237)