Initial CoreDNS setup as MCNS precursor

Serves two internal zones for the Metacircular platform:
- svc.mcp.metacircular.net (service addresses)
- mcp.metacircular.net (node addresses)

Forwards all other queries to 1.1.1.1 and 8.8.8.8. Includes rift
deployment compose with CoreDNS 1.12.1 and zone files mapping
metacrypt and rift to their LAN and Tailscale addresses.

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

Corefile

@@ -0,0 +1,20 @@
+# Internal zone for Metacircular service discovery.
+# Authoritative for svc.mcp.metacircular.net and mcp.metacircular.net.
+# Everything else forwards to public resolvers.
+
+svc.mcp.metacircular.net {
+    file /etc/coredns/zones/svc.mcp.metacircular.net.zone
+    log
+}
+
+mcp.metacircular.net {
+    file /etc/coredns/zones/mcp.metacircular.net.zone
+    log
+}
+
+. {
+    forward . 1.1.1.1 8.8.8.8
+    cache 30
+    log
+    errors
+}