orion: route mcp.metacircular.net zone to rift via resolved

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

hw/orion/default.nix

@@ -6,4 +6,15 @@
     ../../configs/qemu.nix
     ../../configs/mcpkg.nix
   ];
+
+  # Route internal Metacircular zones to rift's CoreDNS (MCNS precursor).
+  # Uses systemd-resolved domain routing so rift handles only *.mcp.metacircular.net
+  # while DHCP/Tailscale DNS handles everything else.
+  networking.nameservers = [
+    "192.168.88.181"
+    "100.95.252.120"
+  ];
+  services.resolved.domains = [
+    "~mcp.metacircular.net"
+  ];
 }