ProjectNavigator

This update ensures that the dominant folder is being reset whenever the selection is reset.

The view state now sports a property containing the dominant folder (if any). That is the folder where files ought to be added if a corresponding action is triggered via a main menu item or via a corresponding button in the toolbar or similar.

Move the package over to using the Observation framework, which also requires the use of macOS 14 and iOS 17, respectively.

The FileTree class now directly facilitates getting the (relative) file path of each file and folder contained in the tree.

This release ensures that the top-level item —i.e., the root item, which may be a folder or a singleton file— can also be selected.

This is the initial release of ProjectNavigator. It contains all the basic functionality as demonstrated in the included NavigatorDemo project. The one remaining serious problem is that inplace file name editing on iOS is broken for reasons explained in Issue #14.