对冲管理新增品种筛选，合约下拉去掉品种前缀

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

ft-app/app/templates/positions.html

@@ -16,15 +16,21 @@
 <div class="form-card" style="margin-bottom:28px;">
   <form method="post" action="/positions/round">
     <div style="display:flex;gap:12px;align-items:flex-end;flex-wrap:wrap;">
-      <div class="form-group" style="margin-bottom:0;flex:1;min-width:140px;">
-        <label>合约</label>
-        <select name="contract_code" required>
-          <option value="">-- 选择合约 --</option>
-          {% for c in contracts %}
-          <option value="{{ c }}">{{ c }}</option>
+      <div class="form-group" style="margin-bottom:0;flex:1;min-width:100px;">
+        <label>品种</label>
+        <select id="productSelect" required onchange="filterContracts()">
+          <option value="">--</option>
+          {% for pcode in product_contracts %}
+          <option value="{{ pcode }}">{{ pcode }}</option>
           {% endfor %}
         </select>
       </div>
+      <div class="form-group" style="margin-bottom:0;flex:1;min-width:120px;">
+        <label>合约</label>
+        <select name="contract_code" id="contractSelect" required disabled>
+          <option value="">-- 先选品种 --</option>
+        </select>
+      </div>
       <div class="form-group" style="margin-bottom:0;flex:1;min-width:100px;">
         <label>每日手数 N</label>
         <input type="number" name="daily_hands" value="1" min="1" max="10" required>
@@ -161,4 +167,19 @@
 </div>
 {% endfor %}
 
+<script>
+var productContracts = {{ product_contracts | tojson }};
+function filterContracts() {
+  var prod = document.getElementById('productSelect').value;
+  var sel = document.getElementById('contractSelect');
+  sel.innerHTML = '<option value="">-- 选择合约 --</option>';
+  sel.disabled = !prod;
+  if (prod && productContracts[prod]) {
+    productContracts[prod].forEach(function(c) {
+      var display = c.startsWith(prod) ? c.substring(prod.length) : c;
+      sel.innerHTML += '<option value="' + c + '">' + display + '</option>';
+    });
+  }
+}
+</script>
 {% endblock %}