fix(okx): stop double-counting unrealized PnL in account equity

[Tonghaofeng]

Problem

For OKX accounts, the equity shown in the dashboard (and fed to the AI for position sizing) is inflated by the current unrealized PnL — it only matches the OKX app when the account is flat.

OKXTrader.GetBalance() returns OKX's totalEq as totalWalletBalance. But OKX's totalEq (from /api/v5/account/balance) is the total account equity and already includes unrealized PnL. The generic consumers then apply the fallback formula:

// auto_trader_loop.go / auto_trader_decision.go / auto_trader_orders.go
totalEquity = totalWalletBalance + totalUnrealizedProfit

so the UPL is counted twice: with open positions the displayed equity is off by exactly the current UPL. Position-value caps (position value / equity ratios) are computed against the inflated number as well.

Fix

Match the convention already used by the Hyperliquid and Bitget adapters:

• expose totalEquity directly (= totalEq), which the consumers prefer over the fallback, and
• keep totalWalletBalance UPL-free (= totalEq - usdtUPL), so the fallback path converges to the same correct value.

Testing

• go build ./trader/okx/ passes.
• Verified on a live OKX unified account with open isolated SWAP positions: before the fix the API-reported equity exceeded OKX's totalEq by exactly the current UPL; after the fix it matches totalEq to the cent and tracks the OKX app in real time as UPL fluctuates.

🤖 Generated with Claude Code

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[cla-assistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}