Feature "Wunschziel für heute" entfernen und BWV-Seite ergänzen

Entfernt den Button und die komplette Funktionalität "Wunschziel für
heute" (desired_zip): Seite, Netzwerk-Nachricht, Preference-Konstante,
Übermittlung beim Session-Start sowie alle Übersetzungen. Ergänzt die
neue BWV-Seite samt SetBwvLocationMessage und preferencesRemove-Helfer.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/network_messages/set_bwv_location_message.dart

@@ -0,0 +1,44 @@
+/// Zeitfenster mit Postleitzahl für das Setzen der BWV-Location.
+class BwvTimeWindow {
+  final int fromUtc;
+  final int toUtc;
+  final String postalCode;
+
+  BwvTimeWindow({
+    required this.fromUtc,
+    required this.toUtc,
+    required this.postalCode,
+  });
+
+  Map<String, dynamic> toJson() => {
+        'fromUtc': fromUtc,
+        'toUtc': toUtc,
+        'postalCode': postalCode,
+      };
+}
+
+/// Payload für das Topic `set_bwv_location`.
+class SetBwvLocationMessage {
+  final int timestamp;
+  final BwvTimeWindow? availabilityStart;
+  final BwvTimeWindow? bwvLocationPreference;
+
+  SetBwvLocationMessage({
+    required this.timestamp,
+    this.availabilityStart,
+    this.bwvLocationPreference,
+  });
+
+  Map<String, dynamic> toJson() {
+    final map = <String, dynamic>{'timestamp': timestamp};
+
+    if (availabilityStart != null) {
+      map['availabilityStart'] = availabilityStart!.toJson();
+    }
+    if (bwvLocationPreference != null) {
+      map['bwvLocationPreference'] = bwvLocationPreference!.toJson();
+    }
+
+    return map;
+  }
+}

lib/network_messages/set_desired_zip_message.dart

@@ -1,15 +0,0 @@
-import 'package:json_annotation/json_annotation.dart';
-
-part 'set_desired_zip_message.g.dart';
-
-@JsonSerializable()
-class SetDesiredZipMessage {
-  @JsonKey(name: "desired_zip")
-  late String desiredZip;
-
-  SetDesiredZipMessage();
-
-  factory SetDesiredZipMessage.fromJson(Map<String, dynamic> json) => _$SetDesiredZipMessageFromJson(json);
-
-  Map<String, dynamic> toJson() => _$SetDesiredZipMessageToJson(this);
-}

lib/network_messages/set_desired_zip_message.g.dart

@@ -1,17 +0,0 @@
-// GENERATED CODE - DO NOT MODIFY BY HAND
-
-part of 'set_desired_zip_message.dart';
-
-// **************************************************************************
-// JsonSerializableGenerator
-// **************************************************************************
-
-SetDesiredZipMessage _$SetDesiredZipMessageFromJson(
-        Map<String, dynamic> json) =>
-    SetDesiredZipMessage()..desiredZip = json['desired_zip'] as String;
-
-Map<String, dynamic> _$SetDesiredZipMessageToJson(
-        SetDesiredZipMessage instance) =>
-    <String, dynamic>{
-      'desired_zip': instance.desiredZip,
-    };

lib/network_messages/start_session_message.dart

@@ -4,9 +4,6 @@ part 'start_session_message.g.dart';
 
 @JsonSerializable()
 class StartSessionMessage {
-  @JsonKey(name: "desired_zip")
-  late String desiredZip;
-
   StartSessionMessage();
 
   factory StartSessionMessage.fromJson(Map<String, dynamic> json) => _$StartSessionMessageFromJson(json);

lib/network_messages/start_session_message.g.dart

@@ -7,10 +7,8 @@ part of 'start_session_message.dart';
 // **************************************************************************
 
 StartSessionMessage _$StartSessionMessageFromJson(Map<String, dynamic> json) =>
-    StartSessionMessage()..desiredZip = json['desired_zip'] as String;
+    StartSessionMessage();
 
 Map<String, dynamic> _$StartSessionMessageToJson(
         StartSessionMessage instance) =>
-    <String, dynamic>{
-      'desired_zip': instance.desiredZip,
-    };
+    <String, dynamic>{};