Add OKX trading-account USDC auto-swap and lock exit target while in position.

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

frontend/src/pages/Plan.tsx

@@ -147,7 +147,12 @@ export default function PlanPage() {
   const exitMode = plan?.exit_mode ?? "fixed_usdt";
   const riskBased =
     plan?.risk_based === true || plan?.sizing_mode === "risk_based";
-  const riskLiveOk = !riskBased || plan?.risk_sizing_preview?.ok === true;
+  const riskLocked =
+    open &&
+    (plan?.risk_sizing_locked === true ||
+      plan?.risk_sizing_preview?.locked === true);
+  const riskLiveOk =
+    !riskBased || riskLocked || plan?.risk_sizing_preview?.ok === true;
   const displayPerpQty = riskLiveOk ? (plan?.perp_qty_eth ?? 1) : null;
   const displayOptQty = riskLiveOk ? (plan?.option_qty_eth ?? 2) : null;
   const exitTarget = riskLiveOk
@@ -160,7 +165,7 @@ export default function PlanPage() {
       ? `权利金×${fmt(plan?.premium_exit_multiple ?? 1, 2)}`
       : riskBased
         ? exitTarget != null
-          ? `固定 ${fmt(exitTarget)} U（基数${fmt(plan?.risk_exit_unit ?? 15)}）`
+          ? `${riskLocked ? "锁定 " : "固定 "}${fmt(exitTarget)} U（基数${fmt(plan?.risk_exit_unit ?? 15)}）`
           : `待估算（基数${fmt(plan?.risk_exit_unit ?? 15)}）`
         : `固定 ${fmt(plan?.net_profit_target ?? 15)} U`;
   const riskRatioLabel = `比例${Number(plan?.risk_perp_unit ?? 1)}：${Number(plan?.risk_option_unit ?? 2)}`;
@@ -169,10 +174,14 @@ export default function PlanPage() {
         "以损定仓",
         riskRatioLabel,
         plan?.risk_last_k != null ? `k=${fmt(plan.risk_last_k, 1)}` : null,
-        plan?.risk_sizing_preview?.budget != null
-          ? `预算${fmt(plan.risk_sizing_preview.budget, 2)}U`
-          : null,
-        plan?.risk_sizing_preview?.ok === false
+        riskLocked
+          ? exitTarget != null
+            ? `目标锁定${fmt(exitTarget, 2)}U`
+            : "目标已锁定"
+          : plan?.risk_sizing_preview?.budget != null
+            ? `预算${fmt(plan.risk_sizing_preview.budget, 2)}U`
+            : null,
+        !riskLocked && plan?.risk_sizing_preview?.ok === false
           ? String(plan.risk_sizing_preview.detail || "预览失败")
           : null,
       ]

frontend/src/pages/Settings.tsx

@@ -1474,14 +1474,18 @@ export default function SettingsPage() {
             onToggle={() => setFundsRulesOpen((v) => !v)}
           >
             <p>
-              币种兑换：对齐 OKX 现货市价 USDC-USDT，在<strong>资金账户</strong>
-              内完成 USDT↔USDC。参考价{" "}
+              币种兑换：对齐 OKX 现货市价 USDC-USDT，手动兑换在<strong>资金账户</strong>
+              内完成。参考价{" "}
               {usdcRate != null ? `1 USDC ≈ ${usdcRate.toFixed(4)} USDT` : "—"}。
             </p>
             <p>
               账户划转：仅<strong>资金账户 ↔ 交易账户</strong>
               （USDT/USDC）。OKX 永续与期权均在交易账户，无单独期权资金/期权交易账户。
             </p>
+            <p>
+              自动兑 USDC（仅 OKX SIM/LIVE）：开仓前若<strong>交易账户</strong> USDC
+              不够当前期权所需，则在交易账户内市价 USDT→USDC，目标约「所需×2」；已够开仓则不兑；并预留永续保证金。币安不生效。
+            </p>
           </RulesFold>
 
           <section className="settings-section">