1. Prevent double-close panic on Stop() by using sync.Once in Scheduler,
Brain, and Sentinel; remove duplicate Stop() call in main.go
2. Add trade quantity (100k) and leverage (125x) sanity caps to prevent
LLM hallucinations or input errors from reaching the exchange
3. Mask secrets in onboarding setup state — only store "****" markers in
SystemConfig instead of plaintext API keys/secrets
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
shinchan-zhai
5d6ec35bb4