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

zones/prezhub.com.zone

@@ -0,0 +1,19 @@
+; Zone file for prezhub.com
+; Generated by mcp-vultr
+$ORIGIN prezhub.com.
+$TTL 3600
+
+	300	IN	NS	ns1.vultr.com
+	300	IN	NS	ns2.vultr.com
+	300	IN	A	149.248.39.194
+dev	300	IN	A	45.77.214.114
+cloud	3600	IN	A	104.156.237.74
+dev2	300	IN	A	149.248.33.94
+deploy-test	3600	IN	A	66.42.75.226
+dev3	3600	IN	A	45.77.215.104
+hspres	3600	IN	A	172.30.10.11
+hspres-dev	3600	IN	A	172.30.30.10
+upgrade	3600	IN	A	45.32.230.148
+python3	3600	IN	A	66.42.65.192
+*	300	IN	CNAME	prezhub.com
+	300	IN	MX	10	prezhub.com