Label night-session products and hide day-only symbols at night.

Mark tradable varieties with a night tag; during 21:00-02:30 filter out index futures and other products without night sessions from symbol picker and recommend list.

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

templates/trade.html

@@ -133,6 +133,7 @@
             <div class="card-body">
                 <p class="hint">最大手数 = floor(权益 × 保证金上限 <strong>{{ max_margin_pct }}%</strong> ÷ 1手保证金)；当前权益 <strong class="text-accent" id="rec-capital">{{ '%.2f'|format(capital) }}</strong> 元。
                     {% if sizing_mode == 'fixed' %}仅显示最大手数 ≥ <strong>{{ fixed_lots }}</strong> 手的品种。{% endif %}
+                    {% if night_session %}<span class="text-muted">当前为夜盘时段，品种下拉与下表仅显示有夜盘品种；带「夜盘」标记。</span>{% else %}<span class="text-muted">有夜盘交易的品种带「夜盘」标记。</span>{% endif %}
                     保证金优先读取 CTP 柜台合约信息。
                     {% if recommend_updated_at %}<span class="text-muted">每日后台更新 · 最近 {{ recommend_updated_at }}</span>{% else %}<span class="text-muted" id="rec-updated">等待今日后台刷新…</span>{% endif %}
                 </p>
@@ -173,11 +174,11 @@
                                 <td>
                                     {% if r.main_code and nav_items.market %}
                                     <a href="{{ url_for('market_page', symbol=r.main_code, period='d') }}" class="rec-market-link" title="查看日线 K 线">
-                                        <strong class="{% if r.trend_transition %}trend-name{% endif %}">{{ r.name }}</strong>
+                                        <strong class="{% if r.trend_transition %}trend-name{% endif %}">{{ r.name }}</strong>{% if r.has_night_session %} <span class="night-session-tag">夜盘</span>{% endif %}
                                         <span class="text-accent">{{ r.main_code }}</span>
                                     </a>
                                     {% else %}
-                                    <strong class="{% if r.trend_transition %}trend-name{% endif %}">{{ r.name }}</strong>
+                                    <strong class="{% if r.trend_transition %}trend-name{% endif %}">{{ r.name }}</strong>{% if r.has_night_session %} <span class="night-session-tag">夜盘</span>{% endif %}
                                     <span class="text-accent">{{ r.main_code or r.ths }}</span>
                                     {% endif %}
                                 </td>