Add svc host: NixOS config for TornadoVPS edge node

BIOS boot with GRUB on /dev/xvda, MCP agent via systemd,
mc-proxy and MCNS as containers via MCP agent.

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

hw/svc/disk-config.nix

@@ -0,0 +1,29 @@
+{ lib, ... }:
+
+{
+  disko.devices = {
+    disk = {
+      main = {
+        device = lib.mkDefault "/dev/xvda";
+        type = "disk";
+        content = {
+          type = "gpt";
+          partitions = {
+            boot = {
+              size = "1M";
+              type = "EF02"; # BIOS boot partition for GRUB
+            };
+            root = {
+              size = "100%";
+              content = {
+                type = "filesystem";
+                format = "ext4";
+                mountpoint = "/";
+              };
+            };
+          };
+        };
+      };
+    };
+  };
+}