feat(agent): add baseURL config for custom API endpoint

[synix]

Summary

• Add optional baseURL parameter to AgentConfig, allowing users to configure a custom API endpoint for the Anthropic client
• This enables using Anthropic SDK-compatible providers (e.g., https://docs.bigmodel.cn/cn/guide/develop/claude/introduction)

Motivation

The Anthropic SDK supports a baseURL option to redirect API calls to compatible third-party providers. By exposing this in AgentConfig, openclaw-mini becomes provider-agnostic with zero additional dependencies.

Usage

  const agent = new Agent({
    baseURL: "https://open.bigmodel.cn/api/anthropic",  // Custom API endpoint
    apiKey: "your-zhipuai-api-key",                      // Provider API key
    model: "glm-4.7",                                    // Provider model
    workspaceDir: process.cwd(),
  });