Add expiry profit estimate and remove chain quick-buy button.

Let users enter a target index in the order panel for estimated expiry P&L, and remove the redundant buy button from the options chain row.

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

lib/options/templates/options_panel.html

@@ -49,6 +49,13 @@
                         <div><span class="k">到期平衡</span><span id="opt-order-expiry-be" class="v">—</span></div>
                         <div><span class="k">距平衡</span><span id="opt-order-dist-be" class="v">—</span></div>
                     </div>
+                    <div class="options-estimate-row">
+                        <label class="opt-est-label" for="opt-target-idx">目标位（指数）</label>
+                        <input type="number" id="opt-target-idx" class="opt-target-idx" step="0.1" min="0" placeholder="到期时指数价">
+                        <span class="k">预计盈利</span>
+                        <span id="opt-est-profit" class="v">—</span>
+                        <span class="muted opt-est-note">到期测算，仅供参考</span>
+                    </div>
                     <div class="form-row options-order-mode-row">
                         <label><input type="radio" name="opt-size-mode" value="sheets" checked> 指定张数</label>
                         <input type="number" id="opt-sheets-amount" min="1" step="1" value="1" placeholder="张数">