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/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";
+        };
+      };
+    };
+  };
+}