feat: 正在下载 / 已完成卡片支持点击折叠

对齐历史频道的交互：card-hd 整行可点，箭头 ▾ 旋转，
折叠时 card-hd border-bottom 去掉避免多余分隔线。
已完成卡片的分页器 done-pager 跟 card-bd 联动隐藏。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

module/templates/index.html

@@ -194,6 +194,10 @@
     }
     .card-hd-badge { font-size: 11px; font-weight: 400; color: var(--muted); }
     .card-bd { padding: 12px 14px; }
+    /* 可折叠的 card-hd */
+    .card-hd.collapsible { cursor: pointer; user-select: none; }
+    .card-hd.collapsed { border-bottom: none; }
+    .card-hd-left { display: flex; align-items: center; gap: 6px; }
 
     /* 任务队列总览 */
     .task-banner {
@@ -1042,8 +1046,11 @@
 
   <!-- 正在下载 -->
   <div class="card">
-    <div class="card-hd">
-      <span>正在下载</span>
+    <div class="card-hd collapsible" id="dl-head" onclick="toggleDl()">
+      <div class="card-hd-left">
+        <span class="hist-arrow" id="dl-arrow">▾</span>
+        <span>正在下载</span>
+      </div>
       <span class="card-hd-badge" id="dl-badge">0 个文件</span>
     </div>
     <div class="card-bd" id="dl-list">
@@ -1060,8 +1067,11 @@
 
   <!-- 已完成 -->
   <div class="card">
-    <div class="card-hd">
-      <span>已完成</span>
+    <div class="card-hd collapsible" id="done-head" onclick="toggleDone()">
+      <div class="card-hd-left">
+        <span class="hist-arrow" id="done-arrow">▾</span>
+        <span>已完成</span>
+      </div>
       <span class="card-hd-badge" id="done-badge">0 个文件</span>
     </div>
     <div class="card-bd" id="done-list">
@@ -1082,6 +1092,8 @@
   let dlState = '{{ download_state }}';
   let validatedChannel = null;
   let histOpen = true;
+  let dlOpen = true;
+  let doneOpen = true;
   let setupStatus = {};
   let wizStep = 0;
   let donePage = 1;
@@ -1174,6 +1186,29 @@
     document.getElementById('hist-arrow').className = 'hist-arrow' + (histOpen ? '' : ' closed');
   }
 
+  // ── 正在下载 / 已完成 折叠 ──
+  function toggleDl() {
+    dlOpen = !dlOpen;
+    document.getElementById('dl-list').style.display = dlOpen ? '' : 'none';
+    document.getElementById('dl-arrow').className = 'hist-arrow' + (dlOpen ? '' : ' closed');
+    document.getElementById('dl-head').classList.toggle('collapsed', !dlOpen);
+  }
+  function toggleDone() {
+    doneOpen = !doneOpen;
+    document.getElementById('done-list').style.display = doneOpen ? '' : 'none';
+    document.getElementById('done-arrow').className = 'hist-arrow' + (doneOpen ? '' : ' closed');
+    document.getElementById('done-head').classList.toggle('collapsed', !doneOpen);
+    // 分页器跟 done-list 联动，仅在展开且本来就显示时才恢复
+    const pager = document.getElementById('done-pager');
+    if (!doneOpen) {
+      pager.dataset.hiddenByToggle = pager.style.display !== 'none' ? '1' : '';
+      pager.style.display = 'none';
+    } else if (pager.dataset.hiddenByToggle === '1') {
+      pager.style.display = '';
+      pager.dataset.hiddenByToggle = '';
+    }
+  }
+
   function loadHistory() {
     fetch('/api/channel_history').then(r => r.json()).then(d => {
       const list = document.getElementById('hist-list');
@@ -1649,7 +1684,13 @@
         if (total_pages <= 1) {
           pager.style.display = 'none';
         } else {
-          pager.style.display = 'flex';
+          // 卡片被折叠时不显示分页器，但记下"原本该显示"的状态，展开后由 toggleDone 恢复
+          if (doneOpen) {
+            pager.style.display = 'flex';
+          } else {
+            pager.style.display = 'none';
+            pager.dataset.hiddenByToggle = '1';
+          }
           document.getElementById('done-pager-info').textContent =
             `第 ${page} / ${total_pages} 页，共 ${total} 条`;
           document.getElementById('pg-prev').disabled = page <= 1;