`highlight_resolved_externals` slows down typing in `nushell` when computer is switched from AC to battery power

Describe the bug

I've noticed that while using nushell, if I unplug my laptop, typing in the shell becomes very slow and laggy. If I set highlight_resolved_externals to false this issue does not arise.

How to reproduce

1. Start a nushell session while connected to AC power
2. Switch to battery power
3. Type in session

Expected behavior

I expected nushell to remain as responsive as it was on AC power.

Screenshots

No response

Configuration

Additional context

I am running nushell via Windows Terminal (Preview).

Additionally, I feel as if I remember that the highlight_resolved_externals is making a which call each time to resolve those external commands. If that is the case, I realize that this may not be something that can be fixed necessarily, but was wondering if there was any workarounds, for example:

1. A way to set the variable to false when running on battery power
2. Supplement the performance of which by caching resolved externals
3. Changing the behavior of how often which is run? (Seems to be checking the whole command on keystroke)
4. Allow the externals resolver to be defined manually (Would allow users to define caching manually, use different strategies?)

I am open to any suggestions!

Thank you!

Start by tracing the highlight_resolved_externals path and the external-command resolution or which call described in the report. Reproduce the AC-to-battery transition on Windows with highlighting enabled, then determine whether the change should prevent per-keystroke slowdown, cache resolution, or document a workaround.