Visual Studio Code 1.121 adds built-in Mermaid and HTML previews

Visual Studio Code 1.121 introduces built-in previews for Mermaid diagrams and local HTML files, eliminating the need for extensions to view these formats.

The update also brings experimental support for monitoring and controlling agent sessions on remote machines using the Agents window with SSH or Dev Tunnels.

Terminal tool behavior has been improved through output compression and automatic cleanup of background terminals, streamlining agent-driven workflows.