A type ramp is more than one number — font family, size, weight, line height all travel together.
Composite tokens bundle them. Their $value is an object whose sub-fields are themselves token values, possibly aliases.
Build `text.heading` with $type `typography`. Its $value must include `fontFamily`, `fontSize`, `fontWeight`, and `lineHeight`.
Reuse what already exists: alias `font.display` for `fontFamily`, and `weight.bold` for `fontWeight`.