Fix baseFontSize alias not resolving per theme when token value is a plain number

[Copilot]

When baseFontSize references a token that resolves to a plain numeric value (e.g. 16), all themes used the active theme's baseFontSize during export instead of resolving independently per theme. This broke responsive typography workflows relying on per-theme rem→px conversion.

Root cause

getAliasValue returns a number (via checkAndEvaluateMath) for plain numeric token values. The guard in updateVariables.ts only accepted string, silently discarding the per-theme resolved value:

// before — number return from getAliasValue is silently dropped
if (resolvedBaseFontSize && typeof resolvedBaseFontSize === 'string') {
  themeBaseFontSize = resolvedBaseFontSize;
}

// after — accepts both string and number
if (resolvedBaseFontSize !== null && resolvedBaseFontSize !== undefined
  && (typeof resolvedBaseFontSize === 'string' || typeof resolvedBaseFontSize === 'number')) {
  themeBaseFontSize = String(resolvedBaseFontSize);
}

Tokens stored as '16px' (string) already worked; tokens stored as 16 (number) did not.

Changes

• src/plugin/updateVariables.ts — extend the type guard to accept number returns from getAliasValue when resolving per-theme baseFontSize
• src/plugin/updateVariables.test.ts — add test covering numeric baseline token values across two themes (16 → 16px, 18 → 18px), verifying 1rem resolves differently per theme rather than using the fallback

---

💬 Send tasks to Copilot coding agent from Slack and Teams to turn conversations into code. Copilot posts an update in your thread when it's finished.

[changeset-bot]

🦋 Changeset detected

Latest commit: 6274099

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@tokens-studio/figma-plugin	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

⤵️ 📦 ✨ The artifact was successfully created! Want to test it? Download it here 👀 🎁

[github-actions]

Commit SHA:cf51ab2524e755580a5f48a48490e456fdfb8b6e

Test coverage results 🧪

Code coverage diff between base branch:main and head branch: copilot/fix-token-reference-theme-export 

Status	File	% Stmts	% Branch	% Funcs	% Lines
🟢	total	63.04 (0)	54.93 (0.01)	60.12 (0)	63.34 (0)
🟢	packages/tokens-studio-for-figma/src/plugin/updateVariables.ts	96.15 (0)	71.42 (4.76)	100 (0)	96.15 (0)
🟢	packages/tokens-studio-for-figma/src/utils/mapTokensToVariableInfo.ts	100 (0)	87.5 (12.5)	100 (0)	100 (0)