Network-wide HL trader leaderboard (PnL / ROI / volume ranking)

Ranks every Hyperliquid trader by `pnl`, `roi`, or `vlm` over a performance window (`day` | `week` | `month` | `allTime`), from HL’s own network leaderboard. Account-level totals — NOT split by asset class. `roi` is a fraction (0.0557 = 5.57%). Pass `address` to fetch a single trader’s entry + rank instead of a page. `capturedAt` is the snapshot freshness.