new agent: Update agents.mdx (#469)

steve02081504/fount@793f590

Author: steve02081504

docs/get-started/agents.mdx

@@ -15,6 +15,7 @@ The following agents can be used with an ACP Client:
 - [Code Assistant](https://github.com/stippi/code-assistant?tab=readme-ov-file#configuration)
 - [Docker's cagent](https://github.com/docker/cagent)
 - [fast-agent](https://fast-agent.ai/acp)
+- [fount](https://github.com/steve02081504/fount)
 - [Gemini CLI](https://github.com/google-gemini/gemini-cli)
 - [GitHub Copilot](https://github.com/features/copilot) (in [public preview](https://github.blog/changelog/2026-01-28-acp-support-in-copilot-cli-is-now-in-public-preview/))
 - [Goose](https://block.github.io/goose/docs/guides/acp-clients)