Support stdio transport server on the session/new request in the acp mode.

### Describe the bug

Agent Client Protocol says [All agents MUST support this transport](https://agentclientprotocol.com/protocol/v1/schema#mcpserver) but Copilot CLI has Rejected these stdio servers.

### Affected version

GitHub Copilot CLI 1.0.63

### Steps to reproduce the behavior

1. Create ACP Client and it connect to Copilot CLI
2. request a `session/new` request with `mcpServers` config include the stdio transport servers.
3. Copilot CLI will rejected these stdio servers. (I discovered Copilot CLI says reject in the process log)

### Expected behavior

These will launch correctly stdio transport MCP Servers via `session/new` request

### Additional context

Currently workaround:
mcpServers config pass to copilot cli via `--additional-mcp-config=JSON` args, these works fine.

Is that the behavior correct?

thanks.

Comienza en el controlador del modo ACP para la solicitud session/new y sigue cómo se procesa su configuración mcpServers, comparándola con la ruta --additional-mcp-config que ya funciona. Reproduce la solicitud con un servidor de transporte stdio y verifica que el servidor se inicie correctamente mediante session/new sin ser rechazado.

Escrito por el modelo de indexación a partir del texto del issue.