refactor: consolidate app configurations and utility scripts

- Move 32+ app-specific scripts from features/apps/scripts/ to features/scripts/utils/ for centralized packaging.
- Create individual Nix modules for orphaned app configurations (btop, kitty, tmux, etc.) in features/apps/ using xdg.configFile.
- Fix broken paths in core/system/makima.nix and features/apps/vscode.nix.
- Update VSCode configuration to use the modern 'profiles.default.userSettings' API, resolving deprecation warnings.
- Merge duplicate 'nomarchy-launch-walker' scripts into a single robust utility.
- Remove stale root 'config/' directory.
- Update README.md and docs/creating-themes.md to reflect the new architecture and keybindings.
- Ensure all modules are correctly imported and verified via nix flake check.

core/home/default.nix

@@ -0,0 +1,14 @@
+{ ... }:
+
+{
+  imports = [
+    ./options.nix
+    ./state.nix
+    ./overrides.nix
+    ./behavior.nix
+    ./fonts.nix
+    ./configs.nix
+    ./security.nix
+    ./bash.nix
+  ];
+}