bingo: stop serving bingo.asxp.io

datacenterbingo.xyz resolves now, so the stopgap second hostname is no
longer needed. Drop it from the Traefik rule and the deploy env; the
app-side BINGO_ALT_HOST support stays but is unset.

Assisted-by: Claude:opus-5

.forgejo/workflows/deploy.yaml

@@ -140,7 +140,6 @@ jobs:
             LTC_ADDRESS=${LTC_ADDRESS}
             CRYPTO_ADDRESSES=${CRYPTO_ADDRESSES}
             BINGO_HOST=datacenterbingo.xyz
-            BINGO_ALT_HOST=bingo.asxp.io
             EOF
             chmod 600 /opt/asxpio/.env