Add sideways max-loss to perpetual-options calculator.

Show premium wipeout plus flat round-trip perp fees as case C for both size and points modes.

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

manual_trading_hub/static/index.html

@@ -966,7 +966,7 @@
           <div class="calc-pane-split">
             <div class="calc-input-panel">
               <h2>永期对冲计算器</h2>
-              <p class="calc-hint">永续固定 1 币;单币权利金 = 现价 / 期权杠杆;权利金按全亏;只扣永续开平手续费(各 0.05%).「推仓位」由波动反推期权数量;「推点数」按永续:期权比例反推达目标盈利所需波动.</p>
+              <p class="calc-hint">永续固定 1 币;单币权利金 = 现价 / 期权杠杆;权利金按全亏;只扣永续开平手续费(各 0.05%).「推仓位」由波动反推期权数量;「推点数」按永续:期权比例反推达目标盈利所需波动.横盘最大亏损 = 权利金全亏 + 永续开平同价手续费.</p>
               <form id="calc-po-form" class="calc-form">
                 <div class="calc-form-grid">
                   <label class="calc-field">
@@ -1751,7 +1751,7 @@
   <script src="/assets/chart_draw.js?v=20260720-option-day-1600"></script>
   <script src="/assets/chart.js?v=20260720-option-day-1600"></script>
   <script src="/assets/plan.js?v=20260720-autofill"></script>
-  <script src="/assets/calculator.js?v=20260728-po-2dp"></script>
+  <script src="/assets/calculator.js?v=20260729-po-sideways"></script>
   <script src="/assets/compare.js?v=20260723-compare"></script>
   <script src="/assets/trade_stats_calendar.js?v=3"></script>
   <script src="/assets/archive.js?v=20260724-opt-archive"></script>