feat(studio): support AgentKit remote agents

docs/content/docs/framework/frontend.en.mdx

@@ -41,6 +41,11 @@ VeADK ships a React frontend that renders [A2UI](/en/docs/framework/a2ui) (agent
   and detect the format automatically. You can also browse account-scoped
   AgentKit Skill Spaces and their skills by region and project. Then debug the
   agent beside its configuration.
+  Remote Agents can only be added as child Agents. They are configured through
+  an AgentKit center ID, recall count, region, and OpenAPI endpoint, while their
+  names, descriptions, and capabilities come from Agent Cards returned by the
+  center. The generated internal proxy discovers and mounts matching remote
+  Agents dynamically for each request.
   Initialization, session, and conversation failures show credential-redacted
   error details and Runner logs that can be expanded and copied. The deployment
   page shows the Agent topology on the left, with hover details, configuration

docs/content/docs/framework/frontend.mdx

@@ -38,6 +38,9 @@ VeADK 自带一个 React 前端，用于渲染智能体经由 Google ADK API Ser
   消息渠道、网络、环境变量后部署到 AgentKit。全局标题栏提供跨页面部署任务列表，
   展示 AgentKit 实际生成的 Runtime 名称、地域与进度；运行中的任务可取消并清理资源，
   失败任务可重试。远程 Agent 的拓扑和 Trace 会通过所选 Runtime 的数据面获取。
+  自定义创建中的“远程 Agent”仅可作为子 Agent，通过 AgentKit 智能体中心 ID、
+  召回数量、地域和 OpenAPI 地址配置。名称、描述和能力由中心返回的 Agent Card
+  提供；生成的内部代理会在每轮请求中动态发现和挂载匹配的远程 Agent。
 - **Tracing 观测**：查看本次会话的调用火焰图。
 - **登录**：支持 SSO（VeIdentity / GitHub / Google / 任意 OIDC）或本地用户名。
 

frontend/README.md

@@ -61,13 +61,16 @@ server that `veadk frontend` launches — no separate backend.
   pairs an inspectable Agent topology with configuration export, source download,
   and a code browser/editor dialog, while keeping region, message channel,
   network, and environment settings primary. Local skills accept a dropped
-  folder or ZIP and detect the format automatically. Component forms omit credentials
-  VeADK can resolve automatically,
-  while the Studio server forwards its Volcengine credentials to debug runs and
-  deployed runtimes. A global task list keeps Runtime, region, and progress
+  folder or ZIP and detect the format automatically. Component forms omit
+  credentials that VeADK can resolve automatically, while the Studio server
+  forwards its Volcengine credentials to debug runs and deployed runtimes. A
+  global task list keeps Runtime, region, and progress
   visible across page switches, follows the actual generated Runtime name, and
   supports cancellation or retry. Remote topology and trace requests use the selected
-  Runtime endpoint.
+  Runtime endpoint. The Remote Agent type is available only for child Agents;
+  its generated internal proxy mounts AgentKit A2A center agents dynamically
+  from the center ID, recall count, region, and OpenAPI endpoint. Remote names,
+  descriptions, and capabilities come from the returned Agent Cards.
 - **Auth**: optional VeIdentity SSO, or a local username for dev.
 - **Agent-driven UI (A2UI)**: when an agent emits A2UI, it renders as native
   components (one feature among the above — not required).