get ref as input

.github/workflows/verify-proof.yml

@@ -2,15 +2,22 @@ name: Verify Proofs (Reusable)
 
 on:
   workflow_call:
+    inputs:
+      evm-placeholder-verification-ref:
+        type: string
+        description: "Reference to evm-placeholder-verification repository to checkout at"
 
 jobs:
   verify-proofs:
     runs-on: [self-hosted, Linux, X64, aws_autoscaling]
     steps:
+      - name: Clean up after previous checkout
+        run: chmod +w -R ${GITHUB_WORKSPACE}; rm -rf ${GITHUB_WORKSPACE}/*;
       - name: Checkout code
         uses: actions/checkout@v4
         with:
-          ref: "${{ github.head_ref || github.ref }}"
+          repository: 'NilFoundation/evm-placeholder-verification'
+          ref: ${{ inputs.evm-placeholder-verification-ref }}
       - name: Download artifact
         uses: actions/download-artifact@v4
         with: