fix: use GITHUB_TOKEN instead of PAT_TOKEN for branch sync

.github/workflows/sync-branches.yml

@@ -9,12 +9,14 @@ on:
 jobs:
   sync:
     runs-on: ubuntu-latest
+    permissions:
+      contents: write
     steps:
       - name: Checkout
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
-          token: ${{ secrets.PAT_TOKEN }}
+          token: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Sync branches
         run: |