Require real ask depth for options and hedge opens.

Block mark-as-ask opens, show reference mark when no depth, cap sheets to ask size; leave close paths unchanged. Document in docs/更新文档.md.

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

lib/hedge_plan/templates/hedge_plan_panel.html

@@ -82,7 +82,7 @@
           <label>张数 <span class="hp-unit">期权张</span> <input type="number" step="1" min="1" id="hp-sheets" value="1" /></label>
           <span class="muted" id="hp-premium-line"></span>
         </div>
-        <p class="muted hp-unit-hint">单位说明:权利金结算币=<strong>USDC</strong> · 张数=期权张(整张) · 卖一/买一=价格/张</p>
+        <p class="muted hp-unit-hint">单位说明:权利金结算币=<strong>USDC</strong> · 张数=期权张(整张) · 卖一/买一=价格/张.期权买入仅认真实卖一价且卖一深度&gt;0;无深度不可开仓(链上~为参考估算).</p>
         <div id="hp-opt-bal-line" class="muted hp-quote-line hp-opt-bal-line"></div>
         <div class="form-row hp-action-row">
           <button type="button" class="primary" id="hp-preview-btn">计算</button>