Feat: Add the history field to the agent's system variables. #7322 (#12823)

### What problem does this PR solve?

Feat: Add the history field to the agent's system variables. #7322

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/constants/agent.tsx

@@ -27,6 +27,7 @@ export enum AgentGlobals {
   SysUserId = 'sys.user_id',
   SysConversationTurns = 'sys.conversation_turns',
   SysFiles = 'sys.files',
+  SysHistory = 'sys.history',
 }
 
 export const AgentGlobalsSysQueryWithBrace = `{${AgentGlobals.SysQuery}}`;

web/src/hooks/use-agent-request.ts

@@ -29,7 +29,7 @@ import api from '@/utils/api';
 import { buildMessageListWithUuid } from '@/utils/chat';
 import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
 import { useDebounce } from 'ahooks';
-import { get, set } from 'lodash';
+import { get, isEmpty, set } from 'lodash';
 import { useCallback, useState } from 'react';
 import { useParams, useSearchParams } from 'react-router';
 import {
@@ -103,6 +103,7 @@ export const EmptyDsl = {
     [AgentGlobals.SysUserId]: '',
     [AgentGlobals.SysConversationTurns]: 0,
     [AgentGlobals.SysFiles]: [],
+    [AgentGlobals.SysHistory]: [],
   },
 };
 
@@ -268,6 +269,17 @@ export const useFetchAgent = (): {
       );
       set(data, 'data.dsl.messages', messageList);
 
+      const sysHistoryPath = [
+        'data',
+        'dsl',
+        'globals',
+        AgentGlobals.SysHistory,
+      ];
+
+      if (isEmpty(get(data, sysHistoryPath))) {
+        set(data, sysHistoryPath, []);
+      }
+
       return data?.data ?? {};
     },
   });