Improve content saving, label editing

CHDataManagement/Model/LocalizedPost.swift

@@ -1,9 +1,7 @@
 import Foundation
 import SwiftUI
 
-final class LocalizedPost: ObservableObject {
-
-    unowned let content: Content
+final class LocalizedPost: ChangeObservingItem {
 
     @Published
     var title: String?
@@ -36,7 +34,6 @@ final class LocalizedPost: ObservableObject {
          labels: [ContentLabel] = [],
          pageLinkText: String? = nil,
          linkPreview: LinkPreview = .init()) {
-        self.content = content
         self.title = title
         self.text = text
         self.lastModified = lastModified
@@ -44,6 +41,7 @@ final class LocalizedPost: ObservableObject {
         self.labels = labels
         self.pageLinkText = pageLinkText
         self.linkPreview = linkPreview
+        super.init(content: content)
     }
 
     func contains(_ string: String) -> Bool {