The logic used to determine whether to invoke the in-memory registration or to
delegate the loading of a library is incorrect for xcframework packages - as
these can contain either static or dynamic libraries.
This change instead lets the operating system handle the library request, and if
it fails, it attempts to load from the internal registry.
With this change, xcframeworks containing dynamic libraries work without
workarounds on iOS.
With an additional fallback case courtesy of @bruvzg
This fixes https://github.com/godotengine/godot/issues/112783
- Introduces a SCons builder for Swift files
- Increases the minimum deployment targets to iOS 14.0, and visionOS 26.0.
- Replaces manually UIWindow management by a SwiftUI instantiated app.
