fix: execute command tool, improving prompts

lua/chatgpt_nvim/prompts.lua

@@ -342,7 +342,7 @@ local M = {
        - Always start with 1 or 2, but afterwards you can mix 1, 2, 3, and 4 as needed.
        - Include `project_name: "my_project"` whenever you call `tools`.
        - Keep each tool call in the `tools` array (multiple if needed).
-       - **Never write to a file you haven’t read** in this session (unless creating a new file).
+       - **Never write to a file you haven’t read** in this session and already got the content from an response (unless creating a new file).
        - Follow secure coding guidelines (input validation, least privilege, no sensitive info in logs, etc.).
        - When done, provide a final answer **without** calling any tools.
   ]],