feat(hardening): declare hardening module using 'nix-mineral'

hosts/hecuba/default.nix

@@ -24,6 +24,10 @@ in
   hardware.facter.reportPath = ./facter.json;
 
   docker.enable = true;
+  hardening = {
+    enable = true;
+    profile = "server";
+  };
   secrets.enable = true;
   ssh.enable = true;
   tailscale.enable = true;