* feat: cosmetic overhaul of native notification popup
* fix: use correct screen default
* feat: move notification test from debug build type to button press
* fix: not debug anymore
* fix: rearrange native notification settings controls
* fix: account for display scaling when positioning notification
* fix: guard against a screen that no longer exists
* fix: safer way to get screens, in case control tree changes
Upon arrival of new records to the backing ObservableCollection, scroll the DataGrid to the last item. However, when the DataGrid is initialized, there's not yet a data context set, so when that happens, then we can listen to the CollectionChanged event to trigger scrolling (only really needed for additions).
In passing, also set the DataGrid to ReadOnly.
In the other two files, minor simplifications/cleanup.