Design handoff is missing mobile breakpoints

What happened — the handoff covers desktop and tablet only. Fourteen screens have no mobile specification.

Impact — front-end is improvising mobile layouts, which means rework once the real specs land. Roughly a sprint of avoidable work.

Next step — design to deliver mobile breakpoints for the fourteen screens, prioritised by build order rather than screen number.

Root cause worth noting — mobile was never explicitly in the handoff definition of done. Fix the checklist, not just the screens.