coredns: docker compose stack with Vultr zone import
- Auto plugin loads zones-prepared/*.zone (regex zone-name extraction)
- scripts/prepare-zones.sh transforms raw Vultr exports:
* synthesizes SOA (omitted by Vultr; CoreDNS requires it)
* prepends @ to leading-TAB apex lines to disambiguate owner inheritance
* dot-terminates NS/MX/CNAME rdata so $ORIGIN doesn't double-suffix
- DNS_PORT defaults to 1053 (5353=avahi, 53=libvirt dnsmasq on this host)
- Forwards non-authoritative queries to 1.1.1.1/1.0.0.1/9.9.9.9
- Makefile targets: prep, up, down, reload, test, logs
- 91 zones loaded