✨(forms) add FieldVariant enum and classic variant tokens

- Add FieldVariant enum with Floating and Classic values
- Add design tokens for classic variant (height, label styles)
- Regenerate cunningham-tokens files

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

packages/react/src/components/Forms/LabelledBox/tokens.ts

@@ -7,4 +7,7 @@ export const tokens = (defaults: DefaultTokens) => ({
     defaults.contextuals.content.semantic.neutral.secondary,
   "label-color--big--disabled":
     defaults.contextuals.content.semantic.neutral.secondary,
+  // Classic variant tokens
+  "classic-label-margin-bottom": defaults.globals.spacings.xs,
+  "classic-label-font-size": defaults.globals.font.sizes.s,
 });