refactor: add plugin for rest client

lua/plugins/util.lua

@@ -6,8 +6,24 @@ return {
 
     {
         "willothy/flatten.nvim",
-        config = true,
-        lazy = true,
+        config = function()
+            require("flatten").setup()
+        end,
+        lazy = false,
         priority = 1001,
     },
+
+    {
+        "rest-nvim/rest.nvim",
+        opts = {},
+        keys = {
+            {
+                "<leader>rt",
+                function()
+                    require("rest-nvim").run()
+                end,
+                desc = "Run the rest request in the current buffer",
+            },
+        },
+    },
 }