Coach Zo architecture overhaul

Zo now maintains full conversation history, sends proactive Monday Briefings to athletes, generates post-session debriefs, and flags nutrition deficits automatically. Response quality improved significantly with the new system prompt architecture.

The previous version of Coach Zo treated each message as a standalone request. The new architecture gives Zo persistent memory of your recent training, PULSE Score trend, nutrition history, and conversation context. That context is passed into every response so Zo's advice is grounded in your actual situation, not a generic answer.

Monday Briefings ship every Sunday night, ready by 06:00 your local time Monday morning. They cover: what you achieved last week, your key win, a Zo assessment of your current fitness trajectory, and a preview of the week ahead. If your nutrition has been consistently under target, that appears in the briefing too, not as a criticism but as data.

Every Zo response still passes through the safety filter before delivery. No dangerous training recommendations, no medical diagnoses, no extreme dietary advice.