feat: start-voip.sh — update DNS locally + start Docker stack

- Removed dns-updater Docker sidecar (curl not available in alpine)
- scripts/start-voip.sh: updates DNS then docker compose up
- update-dns.sh: supports --once flag, runs locally with curl
- All CF API calls forced to IPv4 (-4 flag)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

warzone/deploy/docker/docker-compose.yml

@@ -82,17 +82,6 @@ services:
     networks:
       - backend
 
-  # ─── Dynamic DNS updater (keeps A + AAAA current) ───
-  dns-updater:
-    image: python:3-alpine
-    restart: unless-stopped
-    volumes:
-      - ./update-dns.sh:/update-dns.sh:ro
-    secrets:
-      - cf_api_token
-    entrypoint: ["/bin/sh", "-c", "apk add --no-cache curl > /dev/null 2>&1 && /bin/sh /update-dns.sh"]
-    environment:
-      DNS_UPDATE_INTERVAL: "300"  # 5 minutes
 
 secrets:
   cf_api_token: