Add AI Teammate repositioning design document

Comprehensive design for repositioning altimate from "AI tool" to "AI
teammate" — including trainable knowledge system (/teach, /train,
/feedback), Deep Research mode for multi-step investigations, team
memory that persists via git, and UX reframing from "agent modes" to
"teammate roles."

https://claude.ai/code/session_01V17Kk3qCZFp9ZJiuNYucoq

Author: claude