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/ristretto/apps/neovim.lua

@@ -0,0 +1,31 @@
+return {
+  {
+    "gthelding/monokai-pro.nvim",
+    config = function()
+      require("monokai-pro").setup({
+        filter = "ristretto",
+        override = function()
+          return {
+            NonText = { fg = "#948a8b" },
+            MiniIconsGrey = { fg = "#948a8b" },
+            MiniIconsRed = { fg = "#fd6883" },
+            MiniIconsBlue = { fg = "#85dacc" },
+            MiniIconsGreen = { fg = "#adda78" },
+            MiniIconsYellow = { fg = "#f9cc6c" },
+            MiniIconsOrange = { fg = "#f38d70" },
+            MiniIconsPurple = { fg = "#a8a9eb" },
+            MiniIconsAzure = { fg = "#a8a9eb" },
+            MiniIconsCyan = { fg = "#85dacc" }, -- same value as MiniIconsBlue for consistency
+          }
+        end,
+      })
+      vim.cmd([[colorscheme monokai-pro]])
+    end,
+  },
+  {
+    "LazyVim/LazyVim",
+    opts = {
+      colorscheme = "monokai-pro",
+    },
+  },
+}