fix: bidirectional sync between main and master branches

.github/workflows/sync-branches.yml

@@ -1,8 +1,9 @@
-name: Sync master to main
+name: Sync main and master branches
 
 on:
   push:
     branches:
+      - main
       - master
 
 jobs:
@@ -13,11 +14,27 @@ jobs:
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
+          token: ${{ secrets.GITHUB_TOKEN }}
 
-      - name: Sync master to main
+      - name: Setup Git
         run: |
           git config user.name "github-actions[bot]"
           git config user.email "github-actions[bot]@users.noreply.github.com"
-          git checkout main
-          git merge master --no-edit
-          git push origin main
+
+      - name: Sync branches
+        run: |
+          # Get the branch that was pushed to
+          PUSHED_BRANCH="${GITHUB_REF#refs/heads/}"
+
+          if [ "$PUSHED_BRANCH" = "main" ]; then
+            TARGET_BRANCH="master"
+          else
+            TARGET_BRANCH="main"
+          fi
+
+          echo "Syncing $PUSHED_BRANCH → $TARGET_BRANCH"
+
+          git fetch origin $TARGET_BRANCH || git checkout -b $TARGET_BRANCH
+          git checkout $TARGET_BRANCH
+          git merge origin/$PUSHED_BRANCH --no-edit -m "Sync from $PUSHED_BRANCH"
+          git push origin $TARGET_BRANCH