feat: add a token limit and make it configurable

lua/chatgpt_nvim/config.lua

@@ -3,6 +3,7 @@
 -- 1) Determine the Git root based on the currently opened file.
 -- 2) If no file is open or not in Git repo, fallback to current working directory.
 -- 3) Add support for configuring a list of default prompt blocks ("go-development", "typo3-development", "basic-prompt") that can override the initial prompt if provided.
+-- 4) Add support for configuring a token limit.
 
 local M = {}
 local uv = vim.loop
@@ -57,7 +58,8 @@ function M.load()
   local config = {
     initial_prompt = "",
     directories = { "." },
-    default_prompt_blocks = {}
+    default_prompt_blocks = {},
+    token_limit = 128000
   }
 
   if fd then
@@ -76,6 +78,9 @@ function M.load()
         if type(result.default_prompt_blocks) == "table" then
           config.default_prompt_blocks = result.default_prompt_blocks
         end
+        if type(result.token_limit) == "number" then
+          config.token_limit = result.token_limit
+        end
       end
     end
   else