Update: Restructured plugin folders

lua/plugins/custom/undotree.lua

@@ -0,0 +1,14 @@
+-- lua/custom/plugins/undotree.lua
+return {
+	'mbbill/undotree',
+	keys = {
+		{ '<leader>u', vim.cmd.UndotreeToggle, desc = 'Toggle UndoTree' },
+	},
+	config = function()
+		-- Optional settings
+		vim.g.undotree_WindowLayout = 2 -- vertical split
+		vim.g.undotree_SplitWidth = 30 -- width of undo tree window
+		vim.g.undotree_SetFocusWhenToggle = 1
+		vim.g.undotree_EnableDiff = 1
+	end,
+}