Restructure modules/shared and update all imports

- Delete 2024-12-rework/ folder
- Rename modules/hosts/common to modules/shared, then split into:
  - modules/shared/home/general
  - modules/shared/home/linux
  - modules/shared/nixos
- Update all import paths throughout the codebase
- Update lib/*.nix to use new paths
- Fix hardcoded /Users/${username} to use config.home.homeDirectory
- Update README and examples/flake-structure.nix

modules/shared/files/nvim/lua/plugins/lualine.lua

@@ -0,0 +1,19 @@
+return {
+  "nvim-lualine/lualine.nvim",
+  config = function()
+    require("lualine").setup({
+      options = {
+        icons_enabled = true,
+        -- theme = "dracula-nvim",
+      },
+      sections = {
+        lualine_a = {
+          {
+            "filename",
+            path = 1,
+          },
+        },
+      },
+    })
+  end,
+}