Add explicit noop handling to prevent unnecessary steps

When master is already up-to-date with trinodb/trino (status=noop),
add explicit step to log this and prevent any backup branch creation.

Changes:
- Added 'Skip if already up to date' step for noop status
- Only runs when status == 'noop'
- Ensures no backup branch is created when not needed

This makes the workflow behavior clearer:
- noop: Nothing happens, no backup
- fast-forward: Fast-forward merge, no backup
- rebase: Create backup, rebase, push

Author: sc250072

.github/workflows/sync-upstream.yml

@@ -61,6 +61,10 @@ jobs:
             echo "status=rebase" >> $GITHUB_OUTPUT
           fi
 
+      - name: Skip if already up to date
+        if: steps.check.outputs.status == 'noop'
+        run: echo "✅ Master is already in sync with trinodb/trino. Nothing to do."
+
       - name: Fast-forward
         if: steps.check.outputs.status == 'fast-forward'
         id: fast_forward