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.$id.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';
 
 export async function loader({ request, params }: LoaderFunctionArgs) {
     return json({ error: 'Method not allowed' }, { status: 405 });
@@ -35,11 +34,11 @@ export async function action({ request, params }: LoaderFunctionArgs) {
             console.log(`[API V3] Update Area Dataset: ${id}`, body);
 
             const apiUrl = `${API_BASE_URL}/v3/dify/area-datasets/${id}`;
-            const response = await backendRequest(apiUrl, {
+            const response = await fetch(apiUrl, {
                 method: 'PUT',
                 headers: {
-                    Authorization: `Bearer ${frontendJWT}`,
                     'Content-Type': 'application/json',
+                    'Authorization': `Bearer ${frontendJWT}`,
                 },
                 body: JSON.stringify(body),
             });
@@ -52,10 +51,11 @@ export async function action({ request, params }: LoaderFunctionArgs) {
             console.log(`[API V3] Delete Area Dataset: ${id}`);
 
             const apiUrl = `${API_BASE_URL}/v3/dify/area-datasets/${id}`;
-            const response = await backendRequest(apiUrl, {
+            const response = await fetch(apiUrl, {
                 method: 'DELETE',
                 headers: {
-                    Authorization: `Bearer ${frontendJWT}`,
+                    'Content-Type': 'application/json',
+                    'Authorization': `Bearer ${frontendJWT}`,
                 },
             });