feat: add lazygit and vim-sleuth

plugins/git.nix

@@ -1,6 +1,22 @@
-{...}: {
+{pkgs, ...}: {
   vim.git = {
     gitsigns.enable = true;
     vim-fugitive.enable = true;
   };
+
+  vim.extraPlugins = with pkgs.vimPlugins; {
+    lazygit-nvim = {
+      package = lazygit-nvim;
+      setup = ''require("lazygit").setup({})'';
+    };
+  };
+
+  vim.keymaps = [
+    {
+      key = "<leader>gg";
+      mode = ["n"];
+      action = "<cmd>LazyGit<CR>";
+      desc = "LazyGit";
+    }
+  ];
 }