debug toolbar pane

See https://github.com/lonnieezell/codeigniter4-tasks/blob/develop/docs/vision.md

If you want to work on this, assign the card to yourself and ask any questions here.

Start by reading docs/vision.md, the only project reference in the issue, to determine what the debug toolbar pane is intended to do. The issue does not name an implementation file, entry point, test, or concrete completion criteria, so those details must be established before work can begin.

Written by the indexing model from the issue text.