docs(readme): bump status to 0.20.0, note model field management

Update the Current Status version and add the model field management
tools (addModelField/removeModelField/renameModelField/repositionModelField)
to the recent-features list. Tool catalog already lists them.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: anatoly314

README.md

@@ -908,7 +908,7 @@ This project follows [Semantic Versioning](https://semver.org/) with a pre-1.0 d
     - Will be released when the API is stable and tested
     - Breaking changes will require major version bumps (2.0.0, etc.)
 
-**Current Status**: `0.19.0` - Active beta development. Recent features include batch note creation (`addNotes`), integrated ngrok tunneling (`--ngrok` flag), media file management, model/template management, and comprehensive deck statistics. APIs may change based on feedback and testing.
+**Current Status**: `0.20.0` - Active beta development. Recent features include model field management (`addModelField`, `removeModelField`, `renameModelField`, `repositionModelField`), batch note creation (`addNotes`), integrated ngrok tunneling (`--ngrok` flag), media file management, model/template management, and comprehensive deck statistics. APIs may change based on feedback and testing.
 
 ### MCPB spec evolution