Sync tokens and components with Figma variables and frames ...

- Update primitive palette: add neutral-25, adjust warning-bg to #FEF3E5.
- Add full radius scale (xs/sm/md/lg/xl/2xl/full) from radius.tokens.json.
- Update semantic surfaces/borders from Mode 1 tokens.
- Realign buttons: primary dark, secondary mint, accent yellow, tertiary ghost.
- Realign badges, alerts, cards, inputs, checkbox, radio, switch, modal, toast.
- Update demo palette/utilities and style-guide docs.
- Add exported Figma frames and variables under 'figma design parts/' for reference.