A macOS SwiftUI library window shows an "unsaved changes" warning in its status
bar as soon as a prompt is selected, before the user types anything. Expected:
it should only appear after a real edit.

final class LibraryModel: ObservableObject {
    @Published var draftTitle = ""
    @Published var draftBody = ""
    @Published var dirty = false

    private func loadDraft() {
        guard let prompt = current else { return }
        draftTitle = prompt.title
        draftBody = prompt.body
        dirty = false
    }
}

struct EditPane: View {
    @ObservedObject var model: LibraryModel
    var body: some View {
        TextField("", text: Binding(
            get: { model.draftTitle },
            set: { model.draftTitle = $0; model.dirty = true }))
        TextEditor(text: Binding(
            get: { model.draftBody },
            set: { model.draftBody = $0; model.dirty = true }))
    }
}