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/git-stuff.lua

@@ -0,0 +1,38 @@
+return {
+  {
+    "lewis6991/gitsigns.nvim",
+    config = function()
+      require("gitsigns").setup({
+        current_line_blame = true,
+      })
+
+      vim.keymap.set("n", "<leader gp", ":Gitsigns preview_hunk<CR>", {})
+    end,
+  },
+  {
+    "tpope/vim-fugitive",
+  },
+  {
+    "kdheepak/lazygit.nvim",
+    cmd = {
+      "LazyGit",
+      "LazyGitConfig",
+      "LazyGitCurrentFile",
+      "LazyGitFilter",
+      "LazyGitFilterCurrentFile",
+    },
+    -- optional for floating window border decoration
+    dependencies = {
+      "nvim-lua/plenary.nvim",
+      "nvim-telescope/telescope.nvim",
+    },
+    -- setting the keybinding for LazyGit with 'keys' is recommended in
+    -- order to load the plugin when the command is run for the first time
+    keys = {
+      { "<leader>lg", "<cmd>LazyGit<cr>", desc = "LazyGit" },
+    },
+    config = function()
+      require("telescope").load_extension("lazygit")
+    end,
+  },
+}