Add logout control and show a single locked underlying on hedge select.

Nav gains an exit link when auth is enabled; PO option picker no longer shows unused ETH/BTC toggles.

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

lib/hedge_plan/templates/hedge_plan_panel.html

@@ -67,8 +67,7 @@
         </details>
         <div class="form-row hp-opt-toolbar hp-po-opt-toolbar options-chain-toolbar">
           <span class="hp-uly-lock" id="hp-uly-lock" title="由 HEDGE_PO_MODE 锁定,不可页内切换">
-            <button type="button" class="btn-secondary hp-uly-btn active" data-uly="ETH" disabled>ETH</button>
-            <button type="button" class="btn-secondary hp-uly-btn" data-uly="BTC" disabled>BTC</button>
+            <span class="hp-uly-single" id="hp-uly-single" aria-live="polite">{{ hedge_option_underlying or options_default_underly or 'ETH' }}</span>
           </span>
           <select id="hp-exp-select"><option value="">选择到期日</option></select>
           <span class="hp-oo-seg hp-po-dir-seg" role="group" aria-label="期权类型">
@@ -508,4 +507,4 @@
     </div>
   </div>
 </div>
-<script src="/static/hedge_plan.js?v=62"></script>
+<script src="/static/hedge_plan.js?v=63"></script>