Claude Code v2.1.211: New flags, numerous bug fixes, and enhancements

This patch release for Claude Code introduces a new flag and environment variable to include subagent thinking in stream-json output. It addresses a wide range of bugs, including issues with permission previews, auto mode, session management, and file upload validation. Enhancements include improved terminal performance, more accurate background agent result reporting, and support for scientific notation in environment variables, benefiting developers and engineers using Claude Code.