- New: db_sessions.py with asyncpg pool, session CRUD (upsert) - New: POST/GET/DELETE /api/sessions endpoints - Refactored api.py: _sessions dict replaces _active_runtime singleton - WS accepts ?session= param, sends session_info on connect - Runtime: added session_id, to_state(), restore_state() - Auto-save to Postgres after each message (WS + REST) - Added asyncpg to requirements.txt - PostgreSQL 16 on VPS, tenant DBs: assay_dev, assay_loop42 Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>