Fix TimeZonePickerView

src/TrueWidget/swift/Views/TimeZonePickerView.swift

@@ -57,14 +57,25 @@ struct TimeZonePickerView: View {
 
   @ObservedObject private var source = Source.shared
   @Binding private(set) var abbreviation: String
+  // If passing $abbreviation directly to the Picker's selection, changes may not be reflected in the Picker because $abbreviation might not be an ObservableObject.
+  // Instead, pass $value to the Picker and manually update the changes.
+  @State private(set) var value: String
+
+  init(abbreviation: Binding<String>) {
+    self._abbreviation = abbreviation
+    self.value = abbreviation.wrappedValue
+  }
 
   var body: some View {
-    Picker("", selection: $abbreviation) {
+    Picker("", selection: $value) {
       ForEach(source.timeZones) { timeZone in
         Text(timeZone.label)
           .tag(timeZone.abbreviation)
       }
     }
     .pickerStyle(.menu)
+    .onChange(of: value) { _ in
+      abbreviation = value
+    }
   }
 }