docs: update supported platforms for ACP UI (#1112)

Author: formulahendry

docs/get-started/clients.mdx

@@ -22,7 +22,7 @@ The following projects implement ACP directly, connect ACP agents to other envir
 
 ## Clients and apps
 
-- [ACP UI](https://github.com/formulahendry/acp-ui)
+- [ACP UI](https://github.com/formulahendry/acp-ui) (Windows, macOS, Linux, iOS, Android, Web)
 - [acpx (CLI)](https://github.com/openclaw/acpx)
 - [gemini-cli-desktop](https://github.com/Piebald-AI/gemini-cli-desktop)
 - [Agent Studio](https://github.com/sxhxliang/agent-studio)