1. Change StickToBottom resize mode from "smooth" to "instant" to
prevent scroll position bouncing when new streaming content
arrives faster than the smooth animation completes.
2. Use SDK's preset append mode for system prompts instead of
replacing Claude Code's default prompt. This preserves Claude
Code's built-in awareness of skills (.claude/commands/), working
directory context, and other default behaviors.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
