Fix swap-all balance by reading OKX funding via asset/balances API.

Swap-all targets funding account but ccxt free was often empty; fall back to trading USDT for unified accounts and show balances in errors.

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/exchange/okx_options_lib.py

@@ -439,6 +439,40 @@ def fetch_account_balances_by_type(
     return out, avail
 
 
+def fetch_funding_balances_via_asset_api(
+    ex: ccxt.okx,
+) -> tuple[dict[str, float | None], dict[str, float | None]]:
+    """OKX 资金账户余额(GET /api/v5/asset/balances),比 ccxt fetch_balance 更准确."""
+    out: dict[str, float | None] = {"USDT": None, "USDC": None, "USDG": None}
+    avail: dict[str, float | None] = {"USDT": None, "USDC": None, "USDG": None}
+    try:
+        resp = ex.private_get_asset_balances({})
+        for row in (resp or {}).get("data") or []:
+            if not isinstance(row, dict):
+                continue
+            ccy = str(row.get("ccy") or "").upper()
+            if ccy not in out:
+                continue
+            a = _safe_float(row.get("availBal"))
+            b = _safe_float(row.get("bal")) or _safe_float(row.get("eq"))
+            avail[ccy] = a
+            out[ccy] = b if b is not None else a
+    except Exception:
+        pass
+    return out, avail
+
+
+def _merge_balance_maps(
+    primary: dict[str, float | None],
+    secondary: dict[str, float | None],
+) -> dict[str, float | None]:
+    merged = dict(primary)
+    for ccy, val in secondary.items():
+        if merged.get(ccy) is None and val is not None:
+            merged[ccy] = val
+    return merged
+
+
 def fetch_subaccount_asset_balances(ex: ccxt.okx, sub_acct: str) -> dict[str, float | None]:
     """子账户各币种可用余额(主/子划转「全部」用)."""
     sub = (sub_acct or "").strip()
@@ -489,6 +523,9 @@ def fetch_options_balances(
         return dict(cached)
 
     funding, funding_avail = fetch_account_balances_by_type(ex, "funding")
+    asset_funding, asset_funding_avail = fetch_funding_balances_via_asset_api(ex)
+    funding = _merge_balance_maps(funding, asset_funding)
+    funding_avail = _merge_balance_maps(funding_avail, asset_funding_avail)
     trading, trading_avail = fetch_account_balances_by_type(ex, "trading")
     if trading.get("USDC") is None:
         swap_bal, swap_avail = fetch_account_balances_by_type(ex, "swap")