Remove ineffective /etc/hosts step from workflow

Host-level /etc/hosts must be set on alu directly.
Docker copies host's /etc/hosts to spawned containers,
so buildx will use the internal route automatically.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/build.yml

@@ -16,9 +16,6 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
-      - name: Route registry traffic via internal network
-        run: echo "192.168.86.31 gitea.theriise.net" | sudo tee -a /etc/hosts
-
       - name: Log in to Gitea Container Registry
         uses: docker/login-action@v3
         with: