refactor(sync): drop favorite-folder tracking and deal

reaction_board/web/static/views/system.js

@@ -47,7 +47,6 @@ export async function renderSystem(root) {
       <div><span>采集成功</span><strong>${formatCount(health.ok)}</strong></div>
       <div><span>采集失败</span><strong class="${health.failed ? "danger" : ""}">${formatCount(health.failed)}</strong></div>
       <div><span>在库</span><strong>${formatCount(counts.active)}</strong></div>
-      <div><span>已取消收藏</span><strong>${formatCount(counts.unfaved)}</strong></div>
       <div><span>已失效</span><strong>${formatCount(counts.removed)}</strong></div>
       <div><span>已移出库</span><strong>${formatCount(counts.dropped)}</strong></div>
     </div>
@@ -60,16 +59,16 @@ export async function renderSystem(root) {
     <section class="panel">
       ${sectionHeader("预计下次运行")}
       <div class="status-grid">
-        <div><span>收藏夹同步</span><strong>${escapeHtml(formatDateTime(next.folder_sync))}</strong></div>
         <div><span>搜索发现</span><strong>${escapeHtml(formatDateTime(next.discover))}</strong></div>
         <div><span>每日快照</span><strong>${escapeHtml(formatDateTime(next.snapshot))}</strong></div>
-        <div><span>调度参数</span><strong>${system.schedule.discover_minutes} / ${system.schedule.folder_sync_minutes} 分钟</strong></div>
+        <div><span>发现周期</span><strong>${system.schedule.discover_minutes} 分钟</strong></div>
       </div>
       <p class="section-note">预计时间按配置和最近任务完成时间推算；实际以常驻进程为准。</p>
     </section>
 
     <section class="panel">
-      ${sectionHeader("收藏夹容量")}
+      ${sectionHeader("历史收藏夹")}
+      <p class="section-note">系统已不再同步收藏夹；下列统计仅保留历史来源。收藏夹由人工维护，重排序使用 favsort.py。</p>
       ${(system.folders || []).map((folder) => `
         <div class="capacity-row">
           <div class="capacity-label">
@@ -78,8 +77,8 @@ export async function renderSystem(root) {
           </div>
           <div class="capacity-track"><span style="width:${Math.min(100, folder.ratio * 100)}%"
             class="${folder.warning ? "warning" : ""}"></span></div>
-          <p class="section-note">最近同步 ${escapeHtml(formatDateTime(folder.last_ids_at))}</p>
-        </div>`).join("") || emptyState("未配置收藏夹")}
+          <p class="section-note">历史快照 ${escapeHtml(formatDateTime(folder.last_ids_at))}</p>
+        </div>`).join("") || emptyState("无历史收藏夹记录")}
     </section>
 
     <section class="panel">