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/kanagawa/colors.toml

@@ -0,0 +1,23 @@
+accent = "#7e9cd8"
+cursor = "#c8c093"
+foreground = "#dcd7ba"
+background = "#1f1f28"
+selection_foreground = "#c8c093"
+selection_background = "#2d4f67"
+
+color0 = "#090618"
+color1 = "#c34043"
+color2 = "#76946a"
+color3 = "#c0a36e"
+color4 = "#7e9cd8"
+color5 = "#957fb8"
+color6 = "#6a9589"
+color7 = "#c8c093"
+color8 = "#727169"
+color9 = "#e82424"
+color10 = "#98bb6c"
+color11 = "#e6c384"
+color12 = "#7fb4ca"
+color13 = "#938aa9"
+color14 = "#7aa89f"
+color15 = "#dcd7ba"