Scan resolved tokens for any remaining {reference} strings that weren’t resolved.
Checks both standalone references and inline references within larger strings.
Generate CSS custom properties from a flat token map.
If dark_tokens is provided, tokens differing between light and dark
use the light-dark() function with -on-light / -on-dark primitives.
Deep-merge child token JSON over parent token JSON.
Child values override parent values at the same path.
Parent values not present in child are preserved.
Resolve {reference} strings in token values to their target values.
References use curly-brace syntax: "{color.primary}" resolves to the
value of the token at path color.primary.