Show loaded scripts in a custom explorer section #28521

Today loaded scripts can be accessed via the "Open Loaded Script" action which uses a QuickPick UI.

With the new custom explorer support it is possible to show the loaded scripts in the VS Code explorer.

Challenge: since the QuickPick UI is modal it works well in face of concurrent debug sessions and does not need any events from the DAP.

Whereas a custom explorer is non modal and must be updated whenever scripts are loaded/unloaded and when switching between debug sessions.