Add multi-user support for different machines (#208)

## Summary
- Add per-host `username` option allowing different usernames per
machine
- Create work machine host config (`CB14957.local`) with username
`cohnesor`
- Update all modules to use dynamic username from
`myconfig.constants.username`
- Update standalone home-manager configs to accept username as argument

## Changes
- `modules/config/hosts.nix` - Added `username` option with default
- `modules/config/constants.nix` - Username derives from host config
- `modules/config/user.nix` - Fixed hardcoded usernames
- `modules/features/engineer.nix` - Dynamic NordVPN users and nh flake
path
- `hosts/mac-nix/default.nix` - Uses dynamic username pattern
- `hosts/CB14957.local/default.nix` - New work machine config
- `.config/home-manager/*` - Updated to support multiple users

## Usage
```bash
# Personal machines (use default username)
darwin-rebuild switch --flake .#Conners-MacBook-Air

# Work machine
darwin-rebuild switch --flake .#CB14957.local
```

## Test plan
- [ ] Verify `nix flake check` passes
- [ ] Test rebuild on personal machine
- [ ] Test rebuild on work machine

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added browser integration with selectable extensions and a new browser
input for home configurations.
* Introduced a firefox-addons input and applied its overlay across
platforms.

* **Chores**
* Extended system configuration support for additional macOS and Linux
hosts.
* Made user/home settings configurable per-host (dynamic usernames and
platform-specific home paths).
* Centralized and parameterized user-related options for flexible
multi-machine deployments.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Author: connerohnesorge

.config/home-manager/flake.nix

@@ -1,5 +1,5 @@
 {
-  description = "Home Manager configuration of connerohnesorge";
+  description = "Home Manager configuration";
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
@@ -17,17 +17,38 @@
     ...
   }: {
     homeConfigurations = {
-      # macOS configuration
+      # Personal macOS configuration
       "connerohnesorge@Conners-MacBook-Air.local" = home-manager.lib.homeManagerConfiguration {
-        pkgs = nixpkgs.legacyPackages.aarch64-darwin; # Assuming M1/M2 Mac, use x86_64-darwin for Intel
+        pkgs = nixpkgs.legacyPackages.aarch64-darwin;
+        extraSpecialArgs = {username = "connerohnesorge";};
         modules = [
           ./home-darwin.nix
         ];
       };
 
-      # Linux configuration
+      # Work macOS configuration
+      "cohnesor@CB14957.local" = home-manager.lib.homeManagerConfiguration {
+        pkgs = nixpkgs.legacyPackages.aarch64-darwin;
+        extraSpecialArgs = {username = "cohnesor";};
+        modules = [
+          ./home-darwin.nix
+        ];
+      };
+
+      # Personal Linux configuration
       "connerohnesorge" = home-manager.lib.homeManagerConfiguration {
         pkgs = nixpkgs.legacyPackages.x86_64-linux;
+        extraSpecialArgs = {username = "connerohnesorge";};
+        modules = [
+          stylix.homeManagerModules.stylix
+          ./home.nix
+        ];
+      };
+
+      # Work Linux configuration (if needed)
+      "cohnesor" = home-manager.lib.homeManagerConfiguration {
+        pkgs = nixpkgs.legacyPackages.x86_64-linux;
+        extraSpecialArgs = {username = "cohnesor";};
         modules = [
           stylix.homeManagerModules.stylix
           ./home.nix

.config/home-manager/home-darwin.nix

@@ -2,11 +2,12 @@
   config,
   pkgs,
   lib,
+  username ? "connerohnesorge",
   ...
 }: {
   home = {
-    username = "connerohnesorge";
-    homeDirectory = "/home/connerohnesorge";
+    inherit username;
+    homeDirectory = "/Users/${username}";
 
     # You should not change this value, even if you update Home Manager. If you do
     # want to update the value, then make sure to first check the Home Manager

.config/home-manager/home.nix

@@ -3,11 +3,12 @@
   pkgs,
   lib,
   stylix,
+  username ? "connerohnesorge",
   ...
 }: {
   home = {
-    username = "connerohnesorge";
-    homeDirectory = "/home/connerohnesorge";
+    inherit username;
+    homeDirectory = "/home/${username}";
 
     # You should not change this value, even if you update Home Manager. If you do
     # want to update the value, then make sure to first check the Home Manager

flake.lock

@@ -3,7 +3,17 @@
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
-    zen-browser.url = "github:connerohnesorge/zen-browser-flake";
+    zen-browser = {
+      url = "github:0xc000022070/zen-browser-flake";
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.home-manager.follows = "home-manager";
+    };
+
+    firefox-addons = {
+      url = "github:connerohnesorge/nur-expressions?dir=pkgs/firefox-addons";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     proton-authenticator.url = "github:connerohnesorge/proton-authenticator-flake?ref=0494e1b70724861b4f8e2fb314b744e0591dfbb5";
     proton-authenticator.inputs.nixpkgs.follows = "nixpkgs";
 
@@ -141,7 +151,8 @@
       flake = let
         mkConfigurations = moduleSystem:
           denix.lib.configurations {
-            homeManagerUser = "connerohnesorge";
+            # homeManagerUser is set dynamically per-host via myconfig.host.username
+            # See modules/config/constants.nix and modules/config/home.nix
             inherit moduleSystem;
 
             paths = [./hosts ./modules ./rices];

flake.nix

@@ -0,0 +1,113 @@
+{
+  delib,
+  inputs,
+  pkgs,
+  config,
+  lib,
+  ...
+}: let
+  system = "aarch64-darwin";
+in
+  delib.host {
+    name = "CB14957.local";
+
+    # Work machine username
+    username = "cohnesor";
+
+    rice = "empty";
+    type = "laptop";
+
+    home.home.stateVersion = "24.11";
+    homeManagerSystem = system;
+
+    myconfig = {
+      features = {
+        engineer.enable = true;
+      };
+      programs = {
+        dx.enable = true;
+        catls.enable = true;
+        convert_img.enable = true;
+      };
+    };
+
+    nixos = {
+      imports = [
+        inputs.determinate.nixosModules.default
+      ];
+      nixpkgs.hostPlatform = "x86_64-linux";
+      nixpkgs.config.allowUnfree = true;
+      nixpkgs.config.allowUnsupportedSystem = true;
+      system.stateVersion = "24.11";
+
+      # Minimal file system configuration to prevent assertion failures
+      fileSystems."/" = {
+        device = "/dev/disk/by-label/nixos";
+        fsType = "ext4";
+      };
+
+      boot.loader.systemd-boot.enable = true;
+      boot.loader.efi.canTouchEfiVariables = true;
+    };
+
+    darwin = {myconfig, ...}: {
+      imports = [
+        # inputs.determinate.darwinModules.default
+      ];
+
+      nixpkgs = {
+        hostPlatform = system;
+        config.allowUnfree = true;
+      };
+      nix.enable = false;
+      programs = {
+        direnv = {
+          enable = true;
+          nix-direnv = {
+            enable = true;
+            package = pkgs.nix-direnv;
+          };
+        };
+        ssh = {
+          extraConfig = ''
+            SetEnv TERM=xterm-256color
+          '';
+        };
+      };
+      system = {
+        stateVersion = 5;
+        primaryUser = myconfig.constants.username;
+        defaults = {
+          dock.autohide = true;
+
+          trackpad = {
+            Clicking = true;
+            TrackpadThreeFingerDrag = true;
+            Dragging = true;
+          };
+        };
+      };
+
+      environment = {
+        systemPackages = [
+          # Macos Only
+          pkgs.aerospace
+          pkgs.raycast
+          pkgs.xcodes
+          # Shared
+        ];
+        shells = [pkgs.zsh];
+
+        pathsToLink = ["/share/qemu"];
+        etc."containers/containers.conf.d/99-gvproxy-path.conf".text = ''
+          [engine]
+          helper_binaries_dir = ["${pkgs.gvproxy}/bin"]
+        '';
+      };
+      users.users.${myconfig.constants.username} = {
+        home = "/Users/${myconfig.constants.username}";
+      };
+
+      security.pam.services.sudo_local.touchIdAuth = true;
+    };
+  }

hosts/CB14957.local/default.nix

@@ -46,7 +46,7 @@ in
       boot.loader.efi.canTouchEfiVariables = true;
     };
 
-    darwin = {
+    darwin = {myconfig, ...}: {
       imports = [
         # inputs.determinate.darwinModules.default
       ];
@@ -73,7 +73,7 @@ in
       };
       system = {
         stateVersion = 5;
-        primaryUser = "connerohnesorge";
+        primaryUser = myconfig.constants.username;
         defaults = {
           dock.autohide = true;
 
@@ -101,8 +101,8 @@ in
           helper_binaries_dir = ["${pkgs.gvproxy}/bin"]
         '';
       };
-      users.users.connerohnesorge = {
-        home = "/Users/connerohnesorge";
+      users.users.${myconfig.constants.username} = {
+        home = "/Users/${myconfig.constants.username}";
       };
 
       security.pam.services.sudo_local.touchIdAuth = true;

hosts/mac-nix/default.nix

@@ -16,13 +16,19 @@ delib.module {
   name = "constants";
 
   options.constants = with delib; {
-    # Primary username for the system (used for account creation and home directory)
-    username = readOnly (strOption "connerohnesorge");
+    # Primary username for the system (derived from host configuration)
+    # This allows different usernames per machine (e.g., "connerohnesorge" locally, "cohnesor" at work)
+    username = strOption "connerohnesorge";
 
     # Full display name for the user (used in Git commits and system identification)
     userfullname = readOnly (strOption "Conner Ohnesorge");
 
     # Primary email address (used for Git commits, SSH keys, and notifications)
     useremail = readOnly (strOption "connerohnesorge@outlook.com");
   };
+
+  # Derive username from host configuration
+  myconfig.always = {myconfig, ...}: {
+    constants.username = myconfig.host.username;
+  };
 }