use global state to memorize assistant options

app/lib/features/search_browser/domain/providers.dart

@@ -4,6 +4,7 @@ import 'dart:async';
 
 import 'package:bang_navigator/features/bangs/data/models/bang_data.dart';
 import 'package:bang_navigator/features/bangs/domain/repositories/data.dart';
+import 'package:bang_navigator/features/search_browser/domain/entities/modes.dart';
 import 'package:bang_navigator/features/search_browser/domain/entities/sheet.dart';
 import 'package:bang_navigator/features/search_browser/domain/services/create_tab.dart';
 import 'package:flutter/widgets.dart';
@@ -91,3 +92,39 @@ Stream<BangData?> selectedBangData(SelectedBangDataRef ref, {String? domain}) {
       ref.watch(selectedBangTriggerProvider(domain: domain));
   return repository.watchBang(selectedBangTrigger);
 }
+
+@Riverpod(keepAlive: true)
+class LastUsedAssistantMode extends _$LastUsedAssistantMode {
+  void update(AssistantMode mode) {
+    state = mode;
+  }
+
+  @override
+  AssistantMode build() {
+    return AssistantMode.research;
+  }
+}
+
+@Riverpod(keepAlive: true)
+class ActiveResearchVariant extends _$ActiveResearchVariant {
+  void update(ResearchVariant mode) {
+    state = mode;
+  }
+
+  @override
+  ResearchVariant build() {
+    return ResearchVariant.expert;
+  }
+}
+
+@Riverpod(keepAlive: true)
+class ActiveChatModel extends _$ActiveChatModel {
+  void update(ChatModel model) {
+    state = model;
+  }
+
+  @override
+  ChatModel build() {
+    return ChatModel.gpt4o;
+  }
+}

app/lib/features/search_browser/domain/providers.g.dart

@@ -345,5 +345,56 @@ class _SelectedBangTriggerProviderElement
   @override
   String? get domain => (origin as SelectedBangTriggerProvider).domain;
 }
+
+String _$lastUsedAssistantModeHash() =>
+    r'1255a2754a3ea5ea058d110fd9743897fe103a69';
+
+/// See also [LastUsedAssistantMode].
+@ProviderFor(LastUsedAssistantMode)
+final lastUsedAssistantModeProvider =
+    NotifierProvider<LastUsedAssistantMode, AssistantMode>.internal(
+  LastUsedAssistantMode.new,
+  name: r'lastUsedAssistantModeProvider',
+  debugGetCreateSourceHash: const bool.fromEnvironment('dart.vm.product')
+      ? null
+      : _$lastUsedAssistantModeHash,
+  dependencies: null,
+  allTransitiveDependencies: null,
+);
+
+typedef _$LastUsedAssistantMode = Notifier<AssistantMode>;
+String _$activeResearchVariantHash() =>
+    r'8c65a3f5ead6cc4f9e2af85b607b7a49b0764ee3';
+
+/// See also [ActiveResearchVariant].
+@ProviderFor(ActiveResearchVariant)
+final activeResearchVariantProvider =
+    NotifierProvider<ActiveResearchVariant, ResearchVariant>.internal(
+  ActiveResearchVariant.new,
+  name: r'activeResearchVariantProvider',
+  debugGetCreateSourceHash: const bool.fromEnvironment('dart.vm.product')
+      ? null
+      : _$activeResearchVariantHash,
+  dependencies: null,
+  allTransitiveDependencies: null,
+);
+
+typedef _$ActiveResearchVariant = Notifier<ResearchVariant>;
+String _$activeChatModelHash() => r'675f406af8b4aa92699d59e37b5805a81d03a799';
+
+/// See also [ActiveChatModel].
+@ProviderFor(ActiveChatModel)
+final activeChatModelProvider =
+    NotifierProvider<ActiveChatModel, ChatModel>.internal(
+  ActiveChatModel.new,
+  name: r'activeChatModelProvider',
+  debugGetCreateSourceHash: const bool.fromEnvironment('dart.vm.product')
+      ? null
+      : _$activeChatModelHash,
+  dependencies: null,
+  allTransitiveDependencies: null,
+);
+
+typedef _$ActiveChatModel = Notifier<ChatModel>;
 // ignore_for_file: type=lint
 // ignore_for_file: subtype_of_sealed_class, invalid_use_of_internal_member, invalid_use_of_visible_for_testing_member