feat: 支持服务等级动态切换

- 添加 ServiceTier 类型定义
- 修改 dialogService 接收 serviceTier 参数
- 修改 messageHandler 传递 serviceTier 参数
- 修改 ICHelperPanel 传递 UI 选择的服务等级

src/services/dialogService.ts

@@ -9,7 +9,7 @@ import { startStreamDialog, generateTaskId, SSEController, SSECallbacks } from '
 import { executeToolCall, createToolExecutorContext, ToolExecutorContext } from './toolExecutor';
 import { userInteractionManager } from './userInteraction';
 import { getConfig } from '../config/settings';
-import type { DialogRequest, ToolCallRequest, AskUserEvent, RunMode, ToolConfirmEvent, PlanConfirmEvent } from '../types/api';
+import type { DialogRequest, ToolCallRequest, AskUserEvent, RunMode, ServiceTier, ToolConfirmEvent, PlanConfirmEvent } from '../types/api';
 import { submitToolConfirm, submitAnswer, stopDialog } from './apiClient';
 import { ChatHistoryManager } from '../utils/chatHistoryManager';
 
@@ -316,7 +316,8 @@ export class DialogSession {
   async sendMessage(
     message: string,
     callbacks: DialogCallbacks,
-    mode?: RunMode
+    mode?: RunMode,
+    serviceTier?: ServiceTier  // 新增：服务等级参数
   ): Promise<void> {
     if (this.isActive) {
       callbacks.onError?.('当前有对话正在进行中');
@@ -344,6 +345,7 @@ export class DialogSession {
       message,
       userId: config.userId,
       mode: mode || 'agent',
+      serviceTier: serviceTier || config.serviceTier,  // 优先使用传入的参数
       compactedData: compactedData || undefined,
       newMessages: newMessages.length > 0 ? newMessages : undefined,
       knowledgeData: knowledgeData || undefined