feat(对话): 扩展对话管理支持助手关联

- 对话创建接口支持关联助手ID和系统提示词
- 对话查询接口返回关联的助手信息
- 聊天接口支持使用助手系统提示词
- useConversations Hook 扩展助手相关参数

src/app/api/chat/route.ts

@@ -269,15 +269,26 @@ export async function POST(request: Request) {
         try {
           const cchUrl = settings.cchUrl || 'http://localhost:13500';
 
-          // 获取系统提示词
-          const baseSystemPrompt = conversation.systemPrompt || settings.systemPrompt || DEFAULT_SYSTEM_PROMPT;
+          // 获取系统提示词（叠加模式）
+          // 1. 始终使用 DEFAULT_SYSTEM_PROMPT 作为基础
+          // 2. 如果对话有关联助手的提示词（conversation.systemPrompt），则叠加到默认提示词后面
+          // 3. 助手提示词替代设置页面的自定义提示词，不替代默认提示词
           const currentDate = new Date().toLocaleDateString('zh-CN', {
             year: 'numeric',
             month: 'long',
             day: 'numeric',
             weekday: 'long',
           });
-          const systemPrompt = baseSystemPrompt.replace('{{CURRENT_DATE}}', currentDate);
+          const basePrompt = DEFAULT_SYSTEM_PROMPT.replace('{{CURRENT_DATE}}', currentDate);
+
+          // 叠加助手提示词
+          let systemPrompt = basePrompt;
+          if (conversation.systemPrompt) {
+            systemPrompt = `${basePrompt}\n\n---\n\n## 🎭 当前助手角色设定\n\n${conversation.systemPrompt}`;
+            console.log('[API/chat] 🎭 使用助手提示词:', conversation.systemPrompt.substring(0, 100) + '...');
+          } else {
+            console.log('[API/chat] 📝 无助手提示词，使用默认提示词');
+          }
 
           // 获取温度参数
           const temperature = parseFloat(conversation.temperature || settings.temperature || '0.7');

src/app/api/conversations/[id]/route.ts

@@ -1,6 +1,6 @@
 import { NextResponse } from 'next/server';
 import { db } from '@/drizzle/db';
-import { conversations, messages } from '@/drizzle/schema';
+import { conversations, messages, assistants } from '@/drizzle/schema';
 import { eq, asc, and } from 'drizzle-orm';
 import { getCurrentUser } from '@/lib/auth';
 
@@ -41,9 +41,23 @@ export async function GET(request: Request, { params }: RouteParams) {
       orderBy: [asc(messages.createdAt)],
     });
 
+    // 如果有关联助手，获取助手信息
+    let assistant = null;
+    if (conversation.assistantId) {
+      assistant = await db.query.assistants.findFirst({
+        where: eq(assistants.id, conversation.assistantId),
+      });
+    }
+
     return NextResponse.json({
       ...conversation,
       messages: messageList,
+      assistant: assistant ? {
+        id: assistant.id,
+        name: assistant.name,
+        icon: assistant.icon,
+        description: assistant.description,
+      } : null,
     });
   } catch (error) {
     console.error('Failed to get conversation:', error);
@@ -68,7 +82,7 @@ export async function PUT(request: Request, { params }: RouteParams) {
 
     const { id } = await params;
     const body = await request.json();
-    const { title, isPinned, isArchived } = body;
+    const { title, isPinned, isArchived, model } = body;
 
     // 验证对话属于当前用户
     const existingConversation = await db.query.conversations.findFirst({
@@ -101,6 +115,10 @@ export async function PUT(request: Request, { params }: RouteParams) {
       updateData.isArchived = isArchived;
     }
 
+    if (model !== undefined) {
+      updateData.model = model;
+    }
+
     const [updated] = await db
       .update(conversations)
       .set(updateData)

src/app/api/conversations/route.ts

@@ -48,7 +48,7 @@ export async function POST(request: Request) {
     }
 
     const body = await request.json();
-    const { title, model, tools, enableThinking } = body;
+    const { title, model, tools, enableThinking, assistantId, systemPrompt } = body;
 
     const conversationId = nanoid();
 
@@ -61,6 +61,8 @@ export async function POST(request: Request) {
         tools: tools || [],
         enableThinking: enableThinking || false,
         userId: user.userId, // 关联当前用户
+        assistantId: assistantId || null, // 关联助手
+        systemPrompt: systemPrompt || null, // 对话专属系统提示词（来自助手）
       })
       .returning();
 

src/hooks/useConversations.ts

@@ -3,8 +3,16 @@
 import { useState, useEffect, useCallback } from 'react';
 import type { Conversation, Message } from '@/drizzle/schema';
 
+export interface AssistantInfo {
+  id: number;
+  name: string;
+  icon: string | null;
+  description: string | null;
+}
+
 export interface ConversationWithMessages extends Conversation {
   messages: Message[];
+  assistant?: AssistantInfo | null;
 }
 
 export function useConversations() {
@@ -34,6 +42,8 @@ export function useConversations() {
     model: string;
     tools?: string[];
     enableThinking?: boolean;
+    assistantId?: number;
+    systemPrompt?: string;
   }) => {
     try {
       const response = await fetch('/api/conversations', {
@@ -54,7 +64,7 @@ export function useConversations() {
 
   const updateConversation = useCallback(async (
     conversationId: string,
-    data: { title?: string; isPinned?: boolean; isArchived?: boolean }
+    data: { title?: string; isPinned?: boolean; isArchived?: boolean; model?: string }
   ) => {
     try {
       const response = await fetch(`/api/conversations/${conversationId}`, {