fix: use PAT for checkout to trigger PR checks, GITHUB_TOKEN for PR authorship

Author: clavery

.changeset/test-release-workflow.md

@@ -2,4 +2,4 @@
 '@salesforce/b2c-dx-docs': patch
 ---
 
-Verify release workflow with ci-gate and label-based skip
+Verify release workflow with ci-gate and PAT-triggered checks

.github/workflows/changesets.yml

@@ -20,6 +20,8 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
+        with:
+          token: ${{ secrets.CHANGESETS_TOKEN }}
 
       - name: Setup pnpm
         uses: pnpm/action-setup@fc06bc1257f339d1d5d8b3a19a8cae5388b55320 # v5