ci(omnl): install zip/unzip in-job for act-runner

scripts/omnl/build-transaction-package-zip.sh and the smoke script
require 'zip' and 'unzip' binaries; act-runner's default image does
not ship either. Install them idempotently before the smoke step
(same pattern used in smom-dbis-138 CI hardening PR #2).

Co-Authored-By: Nakamoto, S <defi@defi-oracle.io>

.gitea/workflows/validate-omnl-rail.yml

@@ -27,6 +27,15 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
 
+      - name: Install zip/unzip (act-runner image may lack them)
+        run: |
+          need=""
+          command -v zip   >/dev/null 2>&1 || need="$need zip"
+          command -v unzip >/dev/null 2>&1 || need="$need unzip"
+          if [ -n "$need" ]; then
+            sudo apt-get update && sudo apt-get install -y $need
+          fi
+
       - name: .gitignore and resolve_ids
         run: bash scripts/omnl/validate-rail.sh