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

reaction_board/web/static/views/home.js

@@ -30,7 +30,8 @@ function heatStrip(items) {
 function capacity(folders) {
   if (!folders.length) return "";
   return `<section class="panel capacity-panel">
-    ${sectionHeader("年度收藏夹")}
+    ${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。</p>
     ${folders.map((folder) => `
       <div class="capacity-row">
         <div class="capacity-label">
@@ -39,7 +40,6 @@ function capacity(folders) {
         </div>
         <div class="capacity-track"><span style="width:${Math.min(100, folder.ratio * 100)}%"
           class="${folder.warning ? "warning" : ""}"></span></div>
-        ${folder.warning ? `<p class="warning-text">接近容量上限，请准备新建年度收藏夹。</p>` : ""}
       </div>`).join("")}
   </section>`;
 }
@@ -95,7 +95,7 @@ export async function renderHome(root) {
       ${addedNote}
       <div class="video-list">
         ${added.items.length ? added.items.map((item) => videoCard(item)).join("")
-          : emptyState("最近 7 天没有新入库视频", "收藏夹同步或搜索确认后会出现在这里。")}
+          : emptyState("最近 7 天没有新入库视频", "搜索发现确认或 Telegram 私聊手动入库后会出现在这里。")}
       </div>
     </section>