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>

deploy/docker/docker-compose-rift.yml

@@ -0,0 +1,23 @@
+# CoreDNS on rift — MCNS precursor.
+#
+# Serves the svc.mcp.metacircular.net and mcp.metacircular.net zones.
+# Forwards everything else to 1.1.1.1 and 8.8.8.8.
+#
+# Usage:
+#   docker compose -f deploy/docker/docker-compose-rift.yml up -d
+#
+# To use as the network's DNS server, point clients or the router at
+# rift's IP (192.168.88.181) on port 53.
+
+services:
+  coredns:
+    image: coredns/coredns:1.12.1
+    container_name: mcns-coredns
+    restart: unless-stopped
+    command: -conf /etc/coredns/Corefile
+    ports:
+      - "53:53/udp"
+      - "53:53/tcp"
+    volumes:
+      - ../../Corefile:/etc/coredns/Corefile:ro
+      - ../../zones:/etc/coredns/zones:ro