chore: remove features.old archive and format all files

- Delete home/features.old/ (archived old flat feature modules)
- All content migrated to new profile-based structure
- Run alejandra formatter over 13 changed files
- nix flake check passes cleanly

home/m3tam3re/m3-helios.nix

@@ -1,15 +1,11 @@
 # m3-helios — AdGuard DNS and internal routing server.
 # Context: server | Profiles: (none)
-{
-  lib,
-  ...
-}:
-let
-  homeLib = import ../lib { inherit lib; };
+{lib, ...}: let
+  homeLib = import ../lib {inherit lib;};
 in {
   imports = [
     (homeLib.mkHomeConfig {
-      profiles = [ ];
+      profiles = [];
       context = "server";
     })
     ./home-server.nix
@@ -26,5 +22,4 @@ in {
       nitch.enable = true;
     };
   };
-
 }