Fix label sync workflow JSON parsing (#50)

Pass labels JSON via environment variable and parse with JSON.parse()
instead of using fromJSON() inline in the script. The fromJSON() function
doesn't work correctly when used inline in github-script blocks.

This fixes the workflow failure where labels was being set to `Array`
instead of the actual array contents.

Assisted-by: Claude Code (Sonnet 4.5)

Signed-off-by: Colin Walters <walters@verbum.org>

Author: cgwalters

.github/workflows/sync-labels.yml

@@ -113,10 +113,12 @@ jobs:
 
       - name: Sync labels
         uses: actions/github-script@v8
+        env:
+          LABELS_JSON: ${{ needs.init.outputs.labels }}
         with:
           github-token: ${{ steps.token.outputs.token }}
           script: |
-            const labels = ${{ fromJSON(needs.init.outputs.labels) }};
+            const labels = JSON.parse(process.env.LABELS_JSON);
             const owner = context.repo.owner;
             const repo = '${{ matrix.repo }}';