refactor: implement component-based architecture for enhanced maintainability

- Reorganize directory structure into core/, features/, and themes/
- Colocate application Nix logic, configs, scripts, and theme overrides
- Implement 'Inversion of Control' for theming: apps now pull theme-specific layouts
- Update flake.nix and shared library paths to match the new structure
- Document the new Feature-Centric architecture in README.md

features/apps/scripts/nomarchy-launch-about

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# Launch the fastfetch TUI that gives information about the current system.
+
+exec nomarchy-launch-or-focus-tui "bash -c 'fastfetch; read -n 1 -s'"