feat(home): Add starship cross-shell prompt role

Add a new home-manager role for starship.rs, a fast and customizable
cross-shell prompt written in Rust.

Configuration includes:
- Bash and Zsh integration enabled
- Clean character symbols (> for success, x for error)
- Vi mode indicator support
- Smart directory truncation (4 levels, truncate to repo root)
- Git branch and status display
- Nix shell indicator with snowflake symbol
- Command duration for long-running commands (2s+)
- Disabled noisy modules (language runtimes, cloud providers)

Enabled in: home-desktop, home-laptop-compact, home-live-usb,
home-media-center configurations.

Closes: nixos-configs-uji

home/home-desktop.nix

@@ -23,6 +23,7 @@
     kubectl.enable = true;
     tmux.enable = true;
     plasma-manager.enable = true;
+    starship.enable = true;
   };
 
   targets.genericLinux.enable = true;

home/home-laptop-compact.nix

@@ -23,6 +23,7 @@
     plasma-manager.enable = true;
     emacs.enable = true;
     i3_sway.enable = true;
+    starship.enable = true;
 
     # Launcher wrappers for excluded/optional packages
     launchers = {

home/home-live-usb.nix

@@ -16,6 +16,7 @@
     plasma-manager.enable = true;
     emacs.enable = true;
     i3_sway.enable = true;
+    starship.enable = true;
     # development.enable = false;  # Not needed for live USB
     # communication.enable = false; # Not needed for live USB
     # office.enable = false;       # Not needed for live USB

home/home-media-center.nix

@@ -20,6 +20,7 @@
     plasma-manager.enable = true;
     emacs.enable = true;
     i3_sway.enable = true;
+    starship.enable = true;
     # office.enable = false;    # Not needed for media center
     # sync.enable = false;      # Shared machine, no personal file sync
   };

home/roles/default.nix

@@ -19,5 +19,6 @@
     ./sync
     ./tmux
     ./emacs
+    ./starship
   ];
 }

home/roles/starship/default.nix

@@ -0,0 +1,72 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.home.roles.starship;
+in
+{
+  options.home.roles.starship = {
+    enable = mkEnableOption "starship cross-shell prompt";
+  };
+
+  config = mkIf cfg.enable {
+    programs.starship = {
+      enable = true;
+      enableBashIntegration = true;
+      enableZshIntegration = true;
+
+      settings = {
+        add_newline = true;
+
+        character = {
+          success_symbol = "[>](bold green)";
+          error_symbol = "[x](bold red)";
+          vimcmd_symbol = "[<](bold green)";
+        };
+
+        directory = {
+          truncation_length = 4;
+          truncate_to_repo = true;
+        };
+
+        git_branch = {
+          symbol = "";
+          format = "[$symbol$branch(:$remote_branch)]($style) ";
+        };
+
+        git_status = {
+          format = "([$all_status$ahead_behind]($style) )";
+        };
+
+        nix_shell = {
+          symbol = "";
+          format = "[$symbol$state( \\($name\\))]($style) ";
+        };
+
+        cmd_duration = {
+          min_time = 2000;
+          format = "[$duration]($style) ";
+        };
+
+        # Disable modules that are noisy or rarely needed
+        package.disabled = true;
+        nodejs.disabled = true;
+        python.disabled = true;
+        ruby.disabled = true;
+        java.disabled = true;
+        golang.disabled = true;
+        rust.disabled = true;
+        php.disabled = true;
+        lua.disabled = true;
+        perl.disabled = true;
+        terraform.disabled = true;
+        kubernetes.disabled = true;
+        docker_context.disabled = true;
+        aws.disabled = true;
+        gcloud.disabled = true;
+        azure.disabled = true;
+      };
+    };
+  };
+}

roles/common.nix

@@ -0,0 +1,35 @@
+# Common configuration shared between NixOS and Darwin
+{ lib, pkgs, ... }:
+
+{
+  config = {
+    time.timeZone = "America/Los_Angeles";
+
+    environment.systemPackages = with pkgs; [
+      git
+      glances
+      pciutils
+      tree
+      usbutils
+      vim
+    ];
+
+    nix = {
+      package = pkgs.nix;
+      settings = {
+        experimental-features = [ "nix-command" "flakes" ];
+        max-jobs = "auto";
+        trusted-users = [ "johno" ];
+        substituters = [
+        ];
+      };
+
+      gc = {
+        automatic = true;
+        options = "--delete-older-than 10d";
+      };
+    };
+
+    nixpkgs.config.allowUnfree = true;
+  };
+}

roles/darwin.nix

@@ -7,6 +7,10 @@ let
   setEnvironmentPath = "${config.system.build.setEnvironment}";
 in
 {
+  imports = [
+    ./common.nix
+  ];
+
   config = {
     # Salt manages /etc/bashrc, /etc/zshrc, /etc/zshenv
     # nix-darwin writes to .local variants for nix-specific configuration
@@ -43,8 +47,6 @@ in
       fi
     '';
 
-    time.timeZone = "America/Los_Angeles";
-
     # System preferences
     system.defaults = {
       # Custom keyboard shortcuts
@@ -79,42 +81,5 @@ in
         };
       };
     };
-
-    environment.systemPackages = with pkgs; [
-      git
-      glances
-      pciutils
-      tree
-      usbutils
-      vim
-    ];
-
-    nix = {
-      package = pkgs.nix;
-      # distributedBuilds = true;
-      # buildMachines = [{
-      #   hostName = "z790prors.oglehome";
-      #   system = "x86_64-linux";
-      #   protocol = "ssh-ng";
-      #   sshUser = "johno";
-      #   sshKey = "/root/.ssh/id_ed25519";
-      #   maxJobs = 3;
-      #   speedFactor = 2;
-      # }];
-      settings = {
-        experimental-features = [ "nix-command" "flakes" ];
-        max-jobs = "auto";
-        trusted-users = [ "johno" ];
-        substituters = [
-        ];
-      };
-
-      gc = {
-        automatic = true;
-        options = "--delete-older-than 10d";
-      };
-    };
-
-    nixpkgs.config.allowUnfree = true;
   };
 }

roles/default.nix

@@ -4,6 +4,7 @@ with lib;
 
 {
   imports = [
+    ./common.nix
     ./audio
     ./bluetooth
     ./btrfs
@@ -31,7 +32,6 @@ with lib;
       LC_TELEPHONE = "en_US.UTF-8";
       LC_TIME = "en_US.UTF-8";
     };
-    time.timeZone = "America/Los_Angeles";
 
     services.xserver.xkb = {
       layout = "us";
@@ -49,42 +49,7 @@ with lib;
     # Enable the OpenSSH daemon.
     services.openssh.enable = true;
 
-    environment.systemPackages = with pkgs; [
+    # NixOS-specific gc option (not available on Darwin)
-      git
+    nix.gc.randomizedDelaySec = "14m";
-      glances
-      pciutils
-      tree
-      usbutils
-      vim
-    ];
-
-    nix = {
-      package = pkgs.nix;
-      # distributedBuilds = true;
-      # buildMachines = [{
-      #   hostName = "z790prors.oglehome";
-      #   system = "x86_64-linux";
-      #   protocol = "ssh-ng";
-      #   sshUser = "johno";
-      #   sshKey = "/root/.ssh/id_ed25519";
-      #   maxJobs = 3;
-      #   speedFactor = 2;
-      # }];
-      settings = {
-        experimental-features = [ "nix-command" "flakes" ];
-        max-jobs = "auto";
-        trusted-users = [ "johno" ];
-        substituters = [
-        ];
-      };
-
-      gc = {
-        automatic = true;
-        randomizedDelaySec = "14m";
-        options = "--delete-older-than 10d";
-      };
-    };
-
-    nixpkgs.config.allowUnfree = true;
   };
 }