First step of the cognition control plane (docs/COGNITION.md). The chat turn is now
an explicit society of parts over a shared TurnContext blackboard:
perceive (stub) -> route (session mode) -> compose (tiered prompt) -> deliberate.
- lyra/mind.py (new): TurnContext + the pipeline + assemble(); moved build_messages
and the deliberation helpers here (the assembly belongs in the control plane).
- lyra/chat.py: slimmed to "speak + persist" — calls mind.assemble(), runs the
tool/generation loop, persists. No behavior change (same prompt, same output).
- tests: point test_time/test_chat at mind; add an assemble() structure test;
make test_chat/test_tools hermetic (CHAT_DELIBERATE off so respond() doesn't make
a real LLM call). Suite 86 green in ~5s, ruff clean, no import cycle.
This is the frame; perceive/route/learn get filled in next phases — each opt-in.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
