fix(hold-history): switch all metrics from container count to QTY sum

Rename page title to "Hold 歷史績效". Change trend, reason pareto, and
duration derivation to use QTY-based counting so cards, trend chart, and
analytical charts are consistent with each other.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

frontend/src/hold-history/App.vue

@@ -487,7 +487,7 @@ onMounted(() => {
   <div class="dashboard hold-history-page">
     <header class="header hold-history-header">
       <div class="header-left">
-        <h1>Hold 歷史績效 Dashboard</h1>
+        <h1>Hold 歷史績效</h1>
         <span class="hold-type-badge">{{ holdTypeLabel }}</span>
       </div>
       <div class="header-right">