v0.4.2

Fixed

• 🔧 Tool calls no longer jump to the top during streaming. Fixed a regression from 0.4.1 where tool call indicators appeared at the very top of the assistant message while streaming, instead of in their correct position after the preceding text. They would snap back to the correct position only after the response completed. Caused by a premature text buffer flush in the usage event handler that was left over from the pre-parallel-execution refactor.