Motion 14.13 adds Auto Mass

This is a small API improvement with meaningful polish for responsive interfaces and interrupted interactions.

• –Velocity preservation should make drag, reorder, and shared-layout transitions feel less discontinuous.
• –Auto Mass reduces manual spring tuning by scaling perceived weight with element size.
• –Larger cards and panels can now settle more naturally than small controls under one shared transition.
• –Developers should test responsive breakpoints, since automatically heavier elements may also feel slower or overly damped.
• –Motion remains a strong low-level option for performant, interruptible UI motion using transforms.