feat: create new home/ directory structure for profile-based config

New structure:
- home/base/        - Always loaded (shell, cli-tools, secrets)
- home/coding/      - Profile-independent dev tooling (editor, lsp, git, agents)
- home/profiles/    - Freely combinable profiles (gaming, media)
- home/desktop/     - Desktop-only (wm, apps, theme)
- home/server/      - Minimal server stub

Migration sources:
- home/features/cli/ → home/base/{shell,cli-tools,secrets}
- home/features/desktop/hyprland,wayland,rofi → home/desktop/wm/
- home/features/desktop/obsidian,office,webapps,crypto → home/desktop/apps/
- home/features/desktop/fonts,theme,wallpapers → home/desktop/theme/
- gaming.nix split → home/profiles/gaming/{steam,gamescope}
- media.nix split  → home/profiles/media/{obs,ffmpeg,yt-dlp,kdenlive,handbrake}

Option namespaces updated:
- features.cli.*  → base.shell.* / base.cliTools.* / base.secrets
- features.desktop.* → desktop.wm.* / desktop.apps.* / desktop.theme.*
- features.desktop.gaming → profiles.gaming.*
- features.desktop.media  → profiles.media.*

Verified: nix flake check passes (warnings only)

home/base/shell/default.nix

@@ -0,0 +1,7 @@
+# Shell aggregator — imports Nushell (primary) and Starship prompt.
+{...}: {
+  imports = [
+    ./nushell.nix
+    ./starship.nix
+  ];
+}

home/base/shell/nushell.nix

@@ -0,0 +1,85 @@
+# Primary shell configuration — Nushell with environment, aliases, and integrations.
+{
+  config,
+  lib,
+  ...
+}:
+with lib; let
+  cfg = config.base.shell.nushell;
+in {
+  options.base.shell.nushell.enable = mkEnableOption "enable nushell";
+
+  config = mkIf cfg.enable {
+    programs.nushell = {
+      enable = true;
+      envFile.text = ''
+        $env.config.show_banner = false
+        $env.NIX_PATH = "nixpkgs=channel:nixos-unstable"
+        $env.NIX_LOG = "iunfo"
+        $env.WEBKIT_DISABLE_COMPOSITING_MODE = "1"
+        $env.TERMINAL = "ghostty"
+        $env.EDITOR = "nvim"
+        $env.VISUAL = "zeditor"
+        $env.FZF_DEFAULT_COMMAND = "fd --type f --exclude .git --follow --hidden"
+        $env.FZF_DEFAULT_OPTS = "--preview='bat --color=always -n {}' --bind 'ctrl-/:toggle-preview' --header 'Press CTRL-Y to copy command into clipboard' --bind 'ctrl-/:toggle-preview' --bind 'ctrl-y:execute-silent(echo -n {2..} | wl-copy)+abort' --color bg:#282a36,bg+:#44475a,fg:#f8f8f2,fg+:#f8f8f2,header:#6272a4,hl:#bd93f9,hl+:#bd93f9,info:#ffb86c,marker:#ff79c6,pointer:#ff79c6,prompt:#50fa7b,spinner:#ffb86c"
+        $env.XDG_DATA_HOME = $"($env.HOME)/.local/share"
+        $env.SSH_AUTH_SOCK = "/run/user/1000/gnupg/S.gpg-agent.ssh"
+        $env.PATH = ($env.PATH | split row (char esep) | append $"($env.HOME)/.cache/.bun/bin" | append $"($env.HOME)/.npm-global/bin" | uniq)
+        $env.NPM_CONFIG_PREFIX = $"($env.HOME)/.npm-global"
+        $env.FLAKE = $"($env.HOME)/p/NIX/nixos-config"
+
+        # Load kestractl-env from agenix
+        if ("/run/agenix/kestractl-env" | path exists) {
+          open /run/agenix/kestractl-env
+            | lines
+            | where {($in | str trim | str length) > 0}
+            | parse "{key}={value}"
+            | update value {str trim -c '"'}
+            | transpose -r -d
+            | load-env
+        }
+      '';
+
+      configFile.text = ''
+        # Aliases
+        alias .. = cd ..
+        alias ... = cd ...
+        alias h = cd $env.HOME
+        alias b = yazi
+        alias lt = eza --tree --level=2 --long --icons --git
+        alias grep = rg
+        alias just = just --unstable
+
+        alias node = bun
+        alias npx = bunx
+
+        alias n = nix
+        alias nd = nix develop -c $nu.current-shell
+        alias ns = nix shell
+        alias nsn = nix shell nixpkgs#
+        alias nb = nix build
+        alias nbn = nix build nixpkgs#
+        alias nf = nix flake
+
+        alias nr = sudo nixos-rebuild --flake .
+        alias nrs = sudo nixos-rebuild switch --flake .#(sys host | get hostname)
+        alias snr = sudo nixos-rebuild --flake .
+        alias snrs = sudo nixos-rebuild --flake . switch
+        alias hm = home-manager --flake .
+        alias hms = home-manager --flake . switch
+        alias hmr = do { cd ~/projects/nix-configurations; nix flake lock --update-input dotfiles; home-manager --flake .#(whoami)@(hostname) switch }
+
+        alias tsu = sudo tailscale up
+        alias tsd = sudo tailscale down
+
+        alias vi = nvim
+        alias vim = nvim
+
+        if (which tv | is-not-empty) {
+          mkdir ($nu.data-dir | path join "vendor/autoload")
+          tv init nu | save -f ($nu.data-dir | path join "vendor/autoload/tv.nu")
+        }
+      '';
+    };
+  };
+}

home/base/shell/starship.nix

@@ -0,0 +1,69 @@
+# Starship cross-shell prompt with nix-colors theming.
+{
+  config,
+  lib,
+  ...
+}:
+with lib; let
+  cfg = config.base.shell.starship;
+in {
+  options.base.shell.starship.enable = mkEnableOption "enable starship prompt";
+
+  config = mkIf cfg.enable {
+    programs.starship = {
+      enable = true;
+      enableFishIntegration = true;
+      enableNushellIntegration = true;
+      settings = {
+        format = "$all$character";
+        palette = "universal";
+
+        palettes.universal = {
+          background = "#${config.colorScheme.palette.base00}";
+          surface = "#${config.colorScheme.palette.base01}";
+          muted = "#${config.colorScheme.palette.base03}";
+          text = "#${config.colorScheme.palette.base05}";
+          bright = "#${config.colorScheme.palette.base07}";
+          accent1 = "#${config.colorScheme.palette.base08}";
+          accent2 = "#${config.colorScheme.palette.base09}";
+          accent3 = "#${config.colorScheme.palette.base0A}";
+          accent4 = "#${config.colorScheme.palette.base0B}";
+          accent5 = "#${config.colorScheme.palette.base0C}";
+          accent6 = "#${config.colorScheme.palette.base0D}";
+          accent7 = "#${config.colorScheme.palette.base0E}";
+        };
+
+        character = {
+          success_symbol = "[❯](accent7)";
+          error_symbol = "[❯](accent1)";
+        };
+
+        directory = {
+          style = "accent6";
+          truncation_length = 3;
+          truncate_to_repo = false;
+        };
+
+        git_branch = {
+          style = "accent7";
+        };
+
+        git_status = {
+          style = "accent5";
+        };
+
+        cmd_duration = {
+          style = "accent3";
+        };
+
+        hostname = {
+          style = "accent4";
+        };
+
+        username = {
+          style_user = "accent2";
+        };
+      };
+    };
+  };
+}