Open positions + margin + equity for a wallet on Hyperliquid perps

HL Info `clearinghouseState`. Returns `marginSummary` (account value, total margin used, total notional position), `assetPositions[]` (per-asset entryPx, leverage, liquidationPx, unrealizedPnl, positionValue), and recent `crossMaintenanceMarginUsed`. Public — no auth required, no rate cost beyond standard read.