feat(home-manager): add opt-in my.profiles.home-manager module

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018Sv2QAunLcLo3tS1YsfLgN

modules/environments/default.nix

@@ -8,6 +8,7 @@
     ./development
     ./home-assistant
     ./hyprland
+    ./home-manager
     ./zsh
     ./paperless
     ./prowlarr

modules/environments/home-manager/default.nix

@@ -0,0 +1,21 @@
+{
+  config,
+  lib,
+  inputs,
+  self,
+  ...
+}:
+let
+  cfg = config.my.profiles.home-manager;
+in
+{
+  imports = [ self.inputs.home-manager.nixosModules.home-manager ];
+
+  options.my.profiles.home-manager.enable = lib.mkEnableOption "home-manager integration";
+
+  config = lib.mkIf cfg.enable {
+    home-manager.useGlobalPkgs = true;
+    home-manager.useUserPackages = true;
+    home-manager.extraSpecialArgs = { inherit inputs self; };
+  };
+}