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/templates/alacritty.toml.tpl

@@ -0,0 +1,47 @@
+[colors.primary]
+background = "{{ background }}"
+foreground = "{{ foreground }}"
+
+[colors.cursor]
+text = "{{ background }}"
+cursor = "{{ cursor }}"
+
+[colors.vi_mode_cursor]
+text = "{{ background }}"
+cursor = "{{ cursor }}"
+
+[colors.search.matches]
+foreground = "{{ background }}"
+background = "{{ color3 }}"
+
+[colors.search.focused_match]
+foreground = "{{ background }}"
+background = "{{ color1 }}"
+
+[colors.footer_bar]
+foreground = "{{ background }}"
+background = "{{ foreground }}"
+
+[colors.selection]
+text = "{{ selection_foreground }}"
+background = "{{ selection_background }}"
+
+[colors.normal]
+black = "{{ color0 }}"
+red = "{{ color1 }}"
+green = "{{ color2 }}"
+yellow = "{{ color3 }}"
+blue = "{{ color4 }}"
+magenta = "{{ color5 }}"
+cyan = "{{ color6 }}"
+white = "{{ color7 }}"
+
+[colors.bright]
+black = "{{ color8 }}"
+red = "{{ color9 }}"
+green = "{{ color10 }}"
+yellow = "{{ color11 }}"
+blue = "{{ color12 }}"
+magenta = "{{ color13 }}"
+cyan = "{{ color14 }}"
+white = "{{ color15 }}"