FR: option to set the default system prompt

Hi,

I tried modifying the default system prompt to something different than "You are a helpful assistant" by modifying `system_windows.lua` but it doesn't seem to work and stops LazyNvim from updating your package.

Is there a way to set the default systeme prompt system wide? I would really like something more concise and truthful.

Thanks!

Start by examining the referenced system_windows.lua and the plugin's configuration entry points to determine how the default system prompt is currently selected. Define a system-wide configuration path that survives package updates, then verify that it changes the prompt without requiring edits to packaged files.

Written by the indexing model from the issue text.