[Nix] Adds MCP config.

system/hosts/mcp/vars.nix

@@ -0,0 +1,12 @@
+{ config, lib, ...}:
+{
+  options = with lib; with types; {
+    domainName = mkOption { type = str; };
+    localNet = mkOption { type = str; };
+  };
+
+  config = {
+    domainName = "havenisms.com";
+    localNet = "192.168.0.0/16";
+  };
+}