chore: cache uv .venv in cicd

.gitea/workflows/add-new-service.yml

@@ -44,6 +44,7 @@ jobs:
         run: |
           # Only create the venv if the cache didn't restore an existing one
           if [ ! -d ".venv" ]; then
+            echo "Building new .venv"
             uv venv .venv
           fi
           uv sync --directory cli