fix fef in actions/checkout

.github/workflows/foxmesh-ci.yml

@@ -25,7 +25,7 @@ jobs:
     - name: Checkout Target branch
       uses: actions/checkout@v7
       with:
-        ref: ${{ github.event.inputs.target_branch }} || github.ref }}
+        ref: ${{ github.event.inputs.target_branch || github.ref }}
     
     # 2. Set up Python environment
     - name: Set up Python 3.x