Custom extension Context Agent

For #195, we introduced the concept of the extension context agent. The extension context agent is a new feature that allows you to customize the context of the extension.

@autodev.ext-context.test

For example:

{
    "name": "@autodev.ext-context.test",
    "description": "AutoTest",
    "url": "http://127.0.0.1:8765/api/agent/auto-test",
    "responseAction": "Direct"
}