Add support for managing `node_modules/.ignored` folders separately in npkill

Is your feature request related to a problem? Please describe.
When using pnpm after having previously installed packages with npm, the old node_modules directory often gets moved to .ignored. Currently, npkill doesn’t display .ignored folders in a clear or separate way, which makes it harder to identify and manage them.

Describe the solution you'd like
I’d like npkill to show .ignored directories grouped under a collapsible tree (or similar structure) so they’re visually distinct from regular node_modules. Additionally, I’d like an option to delete .ignored separately, (.ignored will be automatically removed if the parent node_modules folder is deleted).

Describe alternatives you've considered
Manually navigating to each .ignored directory and deleting it, which is time-consuming and less convenient.

Additional context
This would be especially useful when switching between package managers (npm → pnpm) to clean up leftover directories without confusion.

No files or tests are named in the issue. Start by locating the TypeScript CLI's directory discovery, tree rendering, and deletion entry points, then trace how node_modules folders are represented. Done means .ignored directories are visually separated in a collapsible group and can be deleted independently.