fix(ci): isolate agent smoke in namespace-capable helper

.gitea/workflows/quality.yaml

@@ -322,12 +322,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-      - name: Install isolated Linux smoke prerequisites
-        run: sudo apt-get update && sudo apt-get install -y iproute2 nftables iptables ipset python3 curl util-linux coreutils
-      - name: Run shipped agent in isolated network and mount namespaces
+      - name: Run shipped agent in a dedicated namespace-capable helper
+        timeout-minutes: 10
         run: |
-          python3 scripts/ci/linux-agent-fixture.test.py
-          sudo bash scripts/ci/linux-netns-smoke.sh
+          sh scripts/ci/linux-agent-container-smoke.test.sh
+          sh scripts/ci/linux-agent-container-smoke.sh
 
   docker-check:
     needs: [changes]