Fix error around --impure

I was seeing a stack trace with this at the bottom:

       error: cannot look up '<home-manager/nixos>' in pure evaluation mode (use '--impure' to override)

After reading a bit at https://nixos-and-flakes.thiscute.world/nixos-with-flakes/start-using-home-manager
I was able to craft this shape which uses home-manager in a flake and
doesn't have the same problem.

sovr/etc/nixos/configuration.nix

@@ -8,8 +8,6 @@
   imports =
     [ # Include the results of the hardware scan.
       ./hardware-configuration.nix
-      # Include the home-manager configuration
-      <home-manager/nixos>
       inputs.sovr.nixosModules.default
     ];
 
@@ -31,15 +29,6 @@
     inputs.sovr.packages."${pkgs.system}".sovr-server
   ];
 
-  home-manager.useGlobalPkgs = true;
-  home-manager.users.eliribble = {
-    home.file.".config/nvim/after/ftplugin/html.vim".source = ./home/eliribble/config/nvim/after/ftplugin/html.vim;
-    home.file.".config/nvim/after/ftplugin/go.vim".source = ./home/eliribble/config/nvim/after/ftplugin/go.vim;
-    home.file.".config/tmux/tmux.conf".source = ./home/eliribble/config/tmux/tmux.conf;
-    home.homeDirectory = "/home/eliribble";
-    home.stateVersion = "24.11";
-    home.username = "eliribble";
-  };
   i18n.defaultLocale = "en_US.UTF-8";
 
   networking = {

sovr/etc/nixos/flake.lock

@@ -1,5 +1,26 @@
 {
   "nodes": {
+    "home-manager": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1736373539,
+        "narHash": "sha256-dinzAqCjenWDxuy+MqUQq0I4zUSfaCvN9rzuCmgMZJY=",
+        "owner": "nix-community",
+        "repo": "home-manager",
+        "rev": "bd65bc3cde04c16755955630b344bc9e35272c56",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "ref": "release-24.11",
+        "repo": "home-manager",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1735264675,
@@ -34,6 +55,7 @@
     },
     "root": {
       "inputs": {
+        "home-manager": "home-manager",
         "nixpkgs": "nixpkgs",
         "sovr": "sovr"
       }
@@ -43,11 +65,11 @@
         "nixpkgs": "nixpkgs_2"
       },
       "locked": {
-        "lastModified": 1735827455,
+        "lastModified": 1735922336,
-        "narHash": "sha256-BpqQu/opMGrr6xUbbFQy2bkEbUSQhbxN4X8M8DRun5I=",
+        "narHash": "sha256-pccBDqwpLTT24mwQTfLxDciSMg95FPhVy683FvUpkj4=",
         "ref": "refs/heads/main",
-        "rev": "950e618c387282e13e4ec865ae37d0e168b4469a",
+        "rev": "85fc0509c232e4073896de480a4dec94bb97547c",
-        "revCount": 60,
+        "revCount": 64,
         "type": "git",
         "url": "file:///home/eliribble/src/sovr.cloud"
       },

sovr/etc/nixos/flake.nix

@@ -3,11 +3,15 @@
 
   inputs = {
     # NixOS official package source, using the nixos-24.11 branch here
+    home-manager = {
+      url = "github:nix-community/home-manager/release-24.11";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11";
     sovr.url = "git+file:///home/eliribble/src/sovr.cloud";
   };
 
-  outputs = { self, nixpkgs, sovr, ... }@inputs: {
+  outputs = { self, home-manager, nixpkgs, sovr, ... }@inputs: {
     nixosConfigurations.sovr = nixpkgs.lib.nixosSystem {
       specialArgs = { inherit inputs; };
       system = "x86_64-linux";
@@ -15,6 +19,12 @@
         # Import the previous configuration.nix we used,
         # so the old configuration file still takes effect
         ./configuration.nix
+	home-manager.nixosModules.home-manager
+	{
+	  home-manager.useGlobalPkgs = true;
+	  home-manager.useUserPackages = true;
+	  home-manager.users.eliribble = import ./home.nix;
+	}
       ];
     };
   };

sovr/etc/nixos/home.nix

@@ -0,0 +1,10 @@
+  { config, pkgs, ... }:
+
+  {
+    home.file.".config/nvim/after/ftplugin/html.vim".source = ./home/eliribble/config/nvim/after/ftplugin/html.vim;
+    home.file.".config/nvim/after/ftplugin/go.vim".source = ./home/eliribble/config/nvim/after/ftplugin/go.vim;
+    home.file.".config/tmux/tmux.conf".source = ./home/eliribble/config/tmux/tmux.conf;
+    home.homeDirectory = "/home/eliribble";
+    home.stateVersion = "24.11";
+    home.username = "eliribble";
+  }