refactor(client): widgets 颜色迁移到 context.tokens

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/test/searchable_option_create_test.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
+import 'package:jiu_client/core/theme/themes.dart';
 import 'package:jiu_client/widgets/searchable_option_field.dart';
 
 void main() {
@@ -8,6 +9,7 @@ void main() {
     Future<int?> Function(String)? onCreate,
   }) {
     return MaterialApp(
+      theme: buildTheme('a'),
       home: Scaffold(
         body: SearchableOptionField(
           options: [OptionItem(id: 1, name: '53度')],