feat: 添加对话应用选择和知识库切换功能

- 新增对话应用管理模块(dify-chat-apps)，支持获取和切换对话应用
- 优化对话应用切换后自动刷新会话列表功能
- 知识库管理页面新增下拉选择器，支持切换不同知识库
- API 层支持 app_id 参数传递，实现多应用会话隔离

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/routes/api.v3.dify.area-datasets.tsx

@@ -6,7 +6,6 @@
 import { type LoaderFunctionArgs, json } from '@remix-run/node';
 import { API_BASE_URL } from '~/config/api-config';
 import { getUserSession } from '~/api/login/auth.server';
-import { request as backendRequest } from '~/api/axios-client';
 
 /**
  * GET - 获取所有知识库绑定列表
@@ -40,10 +39,11 @@ export async function loader({ request }: LoaderFunctionArgs) {
 
         // 转发请求到后端
         const apiUrl = `${API_BASE_URL}/v3/dify/area-datasets?${params}`;
-        const response = await backendRequest(apiUrl, {
+        const response = await fetch(apiUrl, {
             method: 'GET',
             headers: {
-                Authorization: `Bearer ${frontendJWT}`,
+                'Content-Type': 'application/json',
+                'Authorization': `Bearer ${frontendJWT}`,
             },
         });
 
@@ -78,11 +78,11 @@ export async function action({ request }: LoaderFunctionArgs) {
 
         // 转发创建请求到后端
         const apiUrl = `${API_BASE_URL}/v3/dify/area-datasets`;
-        const response = await backendRequest(apiUrl, {
+        const response = await fetch(apiUrl, {
             method: 'POST',
             headers: {
-                Authorization: `Bearer ${frontendJWT}`,
                 'Content-Type': 'application/json',
+                'Authorization': `Bearer ${frontendJWT}`,
             },
             body: JSON.stringify(body),
         });