feat: 添加 file-tree 配置

lua/custom/plugins/file-tree.lua

@@ -0,0 +1,16 @@
+-- 文件树
+return {
+  'nvim-neo-tree/neo-tree.nvim',
+  version = '*',
+  dependencies = {
+    'nvim-lua/plenary.nvim',
+    'nvim-tree/nvim-web-devicons', -- 不严格要求，但推荐
+    'MunifTanjim/nui.nvim',
+  },
+  config = function()
+    require('neo-tree').setup { close_if_last_window = true }
+    vim.keymap.set('n', '<leader>tf', ':Neotree toggle<CR>', { desc = '[T]oggle [F]ileTree' })
+  end,
+}
+
+-- vim: ts=2 sts=2 sw=2 et