Save automatically, improve mocks

CHDataManagement/Model/Item/Item.swift

@@ -1,6 +1,7 @@
 import Foundation
+import Combine
 
-class Item: ObservableObject, Identifiable {
+class Item: ObservableContentItem, Identifiable {
 
     unowned let content: Content
 
@@ -11,17 +12,25 @@ class Item: ObservableObject, Identifiable {
     @Published
     var id: String
 
+    var cancellables = Set<AnyCancellable>()
+
     init(content: Content, id: String) {
         self.content = content
         self.id = id
+
+        observeChanges()
     }
 
+    // MARK: Change observation
+
     func didChange() {
         DispatchQueue.main.async {
             self.changeToggle.toggle()
         }
     }
 
+    // MARK: Paths
+
     func makeCleanAbsolutePath(_ path: String) -> String {
         "/" + makeCleanRelativePath(path)
     }

CHDataManagement/Model/Item/ItemId.swift

@@ -9,3 +9,7 @@ struct ItemId {
 extension ItemId: Codable {
     
 }
+
+extension ItemId: Equatable {
+    
+}