[Feature]: Add Figma Tokens (Tokens Studio) JSON export

[nujovich]

Which surface does this affect?

Export targets (new framework, new file format)

What problem are you trying to solve?

Once Mint produces a clean token set from legacy CSS, designers want the same tokens back in Figma — otherwise the design file and the codebase drift again from day one. The Tokens Studio (formerly Figma Tokens) plugin is the de-facto bridge, and it consumes a specific JSON shape. Users currently have to write that file by hand.

Proposed solution

Add --target tokens-studio that emits a JSON file in the Tokens Studio v2 schema:

{
  "global": {
    "color": {
      "primary": { "500": { "value": "#1976d2", "type": "color" } }
    },
    "spacing": {
      "3": { "value": "12px", "type": "spacing" }
    }
  }
}

Map every Mint category (colors.scale, spacing, typography.fontFamilies, borderRadius, shadows) to the corresponding type so the plugin renders them correctly.

Alternatives you considered

• Style Dictionary export (filed separately) — different consumer; designers don't run style-dictionary build.
• W3C Design Tokens Community Group format — promising long-term, but tooling adoption is still thin.

Additional context

Plugin: https://tokens.studio/ • Schema: https://docs.tokens.studio/

Sanity checks

• I searched existing issues and didn't find this proposal.
• This isn't something I could solve with existing CLI flags or playground options.