Current NAV (net asset value) of a bound wallet

Real-time liquidation equity for one of the caller org's wallets, in USD. `navUsdc` is the unified cross-provider number (close everything + withdraw → this much). Hyperliquid: `clearinghouseState.marginSummary.accountValue` (served by our node, no rate cost). Polymarket: positions mark-to-market (`data-api /value`) + on-chain USDC.e cash; the `cashUsdc`/`positionsValueUsdc` split is populated for Polymarket only (a margin account has no clean spot split). Cached ~20s with request coalescing.