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

themes/palettes/hackerman/apps/vscode.json

@@ -0,0 +1,4 @@
+{
+  "name": "Hackerman",
+  "extension": "Bjarne.hackerman-nomarchy"
+}