Force apt IPv4 in aarch64 Setup OS to avoid dead IPv6 route to ports.ubuntu.com

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: jbachorik

.github/workflows/test_workflow.yml

@@ -387,6 +387,9 @@ jobs:
       - name: Setup OS
         if: steps.set_enabled.outputs.enabled == 'true'
         run: |
+          # ports.ubuntu.com's IPv6 route is intermittently unreachable from GH-hosted
+          # aarch64 runners; force IPv4 so apt doesn't stall/fail on a dead IPv6 path.
+          echo 'Acquire::ForceIPv4 "true";' | sudo tee /etc/apt/apt.conf.d/99force-ipv4 >/dev/null
           sudo apt update -y
           sudo apt remove -y g++
           sudo apt autoremove -y