✨ feat: Add custom request body editor with persistent message storage

- Add CustomRequestEditor component with JSON validation and real-time formatting
- Implement bidirectional sync between chat messages and custom request body
- Add persistent local storage for chat messages (separate from config)
- Remove redundant System Prompt field in custom mode
- Refactor configuration storage to separate messages and settings

New Features:
• Custom request body mode with JSON editor and syntax highlighting
• Real-time bidirectional synchronization between chat UI and custom request body
• Persistent message storage that survives page refresh
• Enhanced configuration export/import including message data
• Improved parameter organization with collapsible sections

Technical Changes:
• Add loadMessages/saveMessages functions in configStorage
• Update usePlaygroundState hook to handle message persistence
• Refactor SettingsPanel to remove System Prompt in custom mode
• Add STORAGE_KEYS constants for better storage key management
• Implement debounced auto-save for both config and messages
• Add hash-based change detection to prevent unnecessary updates

UI/UX Improvements:
• Disabled state styling for parameters in custom mode
• Warning banners and visual feedback for mode switching
• Mobile-responsive design for custom request editor
• Consistent styling with existing design system

web/src/components/playground/ConfigManager.js

@@ -20,13 +20,21 @@ const ConfigManager = ({
   onConfigImport,
   onConfigReset,
   styleState,
+  messages,
 }) => {
   const { t } = useTranslation();
   const fileInputRef = useRef(null);
 
   const handleExport = () => {
     try {
-      exportConfig(currentConfig);
+      // 在导出前先保存当前配置，确保导出的是最新内容
+      const configWithTimestamp = {
+        ...currentConfig,
+        timestamp: new Date().toISOString(),
+      };
+      localStorage.setItem('playground_config', JSON.stringify(configWithTimestamp));
+
+      exportConfig(currentConfig, messages);
       Toast.success({
         content: t('配置已导出到下载文件夹'),
         duration: 3,
@@ -84,11 +92,31 @@ const ConfigManager = ({
         type: 'danger',
       },
       onOk: () => {
-        clearConfig();
-        onConfigReset();
-        Toast.success({
-          content: t('配置已重置为默认值'),
-          duration: 3,
+        // 询问是否同时重置消息
+        Modal.confirm({
+          title: t('重置选项'),
+          content: t('是否同时重置对话消息？选择"是"将清空所有对话记录并恢复默认示例；选择"否"将保留当前对话记录。'),
+          okText: t('同时重置消息'),
+          cancelText: t('仅重置配置'),
+          okButtonProps: {
+            type: 'danger',
+          },
+          onOk: () => {
+            clearConfig();
+            onConfigReset({ resetMessages: true });
+            Toast.success({
+              content: t('配置和消息已全部重置'),
+              duration: 3,
+            });
+          },
+          onCancel: () => {
+            clearConfig();
+            onConfigReset({ resetMessages: false });
+            Toast.success({
+              content: t('配置已重置，对话消息已保留'),
+              duration: 3,
+            });
+          },
         });
       },
     });