api: Add UserSettings.twentyFourHourTime

Not because we have an immediate need to read this user setting.
Rather, this demonstrates how much boilerplate it would take, with
the setup from the previous commit. As I mentioned there, I think it
would be better if less boilerplate were needed, particularly in the
new subclass of [UserSettingsUpdateEvent]. Hmm.

Author: chrisbobbe

lib/api/model/events.dart

@@ -95,6 +95,8 @@ sealed class UserSettingsUpdateEvent extends Event {
 
   factory UserSettingsUpdateEvent.fromJson(Map<String, dynamic> json) {
     switch (UserSettingName.fromRawString(json['property'] as String)) {
+      case UserSettingName.twentyFourHourTime:
+        return UserSettingsUpdateEventTwentyFourHourTime.fromJson(json);
       case UserSettingName.displayEmojiReactionUsers:
         return UserSettingsUpdateEventDisplayEmojiReactionUsers.fromJson(json);
       case null:
@@ -103,6 +105,22 @@ sealed class UserSettingsUpdateEvent extends Event {
   }
 }
 
+@JsonSerializable(fieldRename: FieldRename.snake)
+class UserSettingsUpdateEventTwentyFourHourTime extends UserSettingsUpdateEvent {
+  final bool value;
+
+  UserSettingsUpdateEventTwentyFourHourTime({
+    required super.id,
+    required this.value,
+  });
+
+  factory UserSettingsUpdateEventTwentyFourHourTime.fromJson(Map<String, dynamic> json) =>
+    _$UserSettingsUpdateEventTwentyFourHourTimeFromJson(json);
+
+  @override
+  Map<String, dynamic> toJson() => _$UserSettingsUpdateEventTwentyFourHourTimeToJson(this);
+}
+
 @JsonSerializable(fieldRename: FieldRename.snake)
 class UserSettingsUpdateEventDisplayEmojiReactionUsers extends UserSettingsUpdateEvent {
   final bool value;

lib/api/model/events.g.dart

@@ -119,6 +119,7 @@ class RecentDmConversation {
 /// in <https://zulip.com/api/register-queue>.
 @JsonSerializable(fieldRename: FieldRename.snake, createFieldMap: true)
 class UserSettings {
+  bool twentyFourHourTime;
   bool? displayEmojiReactionUsers; // TODO(server-6)
 
   // TODO more, as needed. When adding a setting here, please also:
@@ -127,6 +128,7 @@ class UserSettings {
   // (3) handle that new subclass in [PerAccountStore]
 
   UserSettings({
+    required this.twentyFourHourTime,
     this.displayEmojiReactionUsers,
   });
 
@@ -143,6 +145,7 @@ class UserSettings {
 /// to ensure that every setting in [UserSettings] responds to the event.
 @JsonEnum(fieldRename: FieldRename.snake, alwaysCreate: true)
 enum UserSettingName {
+  twentyFourHourTime,
   displayEmojiReactionUsers;
 
   /// Get a [UserSettingName] from a raw, snake-case string we recognize, else null.

lib/api/model/initial_snapshot.dart

@@ -222,6 +222,8 @@ class PerAccountStore extends ChangeNotifier {
     } else if (event is UserSettingsUpdateEvent) {
       assert(debugLog("server event: user_settings/update"));
       switch (event) {
+        case UserSettingsUpdateEventTwentyFourHourTime():
+          userSettings!.twentyFourHourTime = event.value;
         case UserSettingsUpdateEventDisplayEmojiReactionUsers():
           userSettings!.displayEmojiReactionUsers = event.value;
         case UserSettingsUpdateEventUnknown():