总览增加实时汇总：在线/离线、仓位、浮盈、权利金、余额，并按 sim/live 分列。

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

templates/dashboard.html

@@ -10,9 +10,10 @@
   <button type="button" class="btn" id="btn-refresh">刷新</button>
 </section>
 <p class="muted" id="overview-status">加载中…</p>
+<section class="overview-summary" id="overview-summary" hidden></section>
 <div id="overview-grid"></div>
 {% endblock %}
 {% block scripts %}
-<script src="{{ url_for('static', filename='hub.js') }}?v=3"></script>
+<script src="{{ url_for('static', filename='hub.js') }}?v=4"></script>
 <script>HubOverview.boot();</script>
 {% endblock %}