Update README with API freeze announcement (#704)

Author: rdimitrov

README.md

@@ -6,6 +6,8 @@ The MCP registry provides MCP clients with a list of MCP servers, like an app st
 
 ## Development Status
 
+**2025-10-24 update**: The Registry API has entered an **API freeze (v0.1)** 🎉. For the next month or more, the API will remain stable with no breaking changes, allowing integrators to confidently implement support. This freeze applies to v0.1 while development continues on v0. We'll use this period to validate the API in real-world integrations and gather feedback to shape v1 for general availability. Thank you to everyone for your contributions and patience—your involvement has been key to getting us here!
+
 **2025-09-08 update**: The registry has launched in preview 🎉 ([announcement blog post](https://blog.modelcontextprotocol.io/posts/2025-09-08-mcp-registry-preview/)). While the system is now more stable, this is still a preview release and breaking changes or data resets may occur. A general availability (GA) release will follow later. We'd love your feedback in [GitHub discussions](https://github.com/modelcontextprotocol/registry/discussions/new?category=ideas) or in the [#registry-dev Discord](https://discord.com/channels/1358869848138059966/1369487942862504016) ([joining details here](https://modelcontextprotocol.io/community/communication)).
 
 Current key maintainers: