Risk x-ray for a whole watchlist or portfolio in one call. Pass `?tickers=AAPL,MSFT,NVDA` (up to 25; optional `?weights=`). Returns per-holding price, sector and cap, plus portfolio concentration (top-weight, Herfindahl, diversification score), sector concentration, market-cap distribution, weighted day performance and risk flags. Replaces dozens of per-holding calls. From x402stock