feat(runtime-control): 注册流程改为通过AuthZ服务

注册现在通过AuthZ进行处理，而登录/运行时查找仍然使用deploy-control。
更新了API调用逻辑，将注册请求从直接调用deploy-control和instance-api
改为统一调用AuthZ服务。

- 修改了注册API路由(/api/runtime/register)以使用callAuthzService
- 更新README.md文档说明新的架构流程
- 添加AUTHZ_API_BASE_URL环境变量配置
- 更新注册页面描述信息
- 移除了不再使用的callDeployControl和callInstanceApi相关代码

auth-portal/src/app/api/runtime/register/route.ts

@@ -1,7 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server';
 
 import type { TokenResponse } from '@/types/auth';
-import { HttpError, callDeployControl, callInstanceApi, normalizeTokenResponse } from '@/lib/runtime-control';
+import { HttpError, callAuthzService } from '@/lib/runtime-control';
 
 function errorStatus(error: unknown): number {
   if (error instanceof HttpError) {
@@ -32,23 +32,13 @@ export async function POST(request: NextRequest) {
       return NextResponse.json({ detail: 'username and password are required' }, { status: 400 });
     }
 
-    const routing = await callDeployControl<{
-      api_base_url?: string;
-      frontend_base_url?: string;
-      public_url?: string;
-    }>('/api/instances/register', {
+    const response = await callAuthzService<TokenResponse>('/portal/register', {
       username,
       email,
       password,
     });
 
-    const response = await callInstanceApi<TokenResponse>(routing.api_base_url || '', '/api/auth/register', {
-      username,
-      email,
-      password,
-    });
-
-    return NextResponse.json(normalizeTokenResponse(response, routing));
+    return NextResponse.json(response);
   } catch (error) {
     return NextResponse.json({ detail: errorDetail(error) }, { status: errorStatus(error) });
   }