fix: 全站页面保活机制、登录拦截优化、UI修复与功能完善

- 移除未登录全页面拦截，改为浏览自由 + 功能使用时弹窗
- 修复PageTransition退出动画卡死导致黑屏的bug
- CanvasPage添加加载中状态避免首次访问黑屏假死
- 全站7个工具页添加页面保活机制，切页后台任务不中断
- 修复未登录时401误触发"用户已在别处登录"弹窗
- 删除MorePage模板板块、微信登录、EcommerceTemplates/SizeTemplate路由
- 剧本评分接入DashScope qwen3.7-max直连API
- 电商视频生成重构为3阶段可视管线（策划→生成图片→生成视频）
- 电商视频保活增强：异步函数直接写localStorage避免卸载丢失
- Workbench侧边栏移除mode过滤，三模式共用同一对话列表
- 首页更新轮播图/背景视频、按钮跳转修正、文案优化
- AppShell顶栏新增网站备案信息按钮
- 多个页面的terminate/cancel按钮覆盖、单镜头重试、批量保存下载

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

src/features/subtitle-removal/SubtitleRemovalPage.tsx

@@ -15,6 +15,7 @@ import {
 import { useCallback, useEffect, useRef, useState, type CSSProperties } from "react";
 import { aiGenerationClient } from "../../api/aiGenerationClient";
 import { waitForTask } from "../../api/taskSubscription";
+import { saveToolTaskState, loadToolTaskState, clearToolTaskState } from "../workbench/toolKeepalive";
 import { getServerBaseUrl, isServerRequestError } from "../../api/serverConnection";
 import { summarizeUrl, formatFileSize, fileToDataUrl } from "../../utils/toolPageUtils";
 import TaskStatusBar from "../../components/TaskStatusBar";
@@ -74,14 +75,26 @@ function SubtitleRemovalPage({
   const [isSavingAsset, setIsSavingAsset] = useState(false);
   const activeTaskIdRef = useRef(activeTaskId);
   activeTaskIdRef.current = activeTaskId;
+  const keepaliveRestoredRef = useRef(false);
+
+  // Keep-alive: restore saved task on mount
+  useEffect(() => {
+    if (keepaliveRestoredRef.current) return;
+    keepaliveRestoredRef.current = true;
+    const saved = loadToolTaskState("subtitle");
+    if (!saved || saved.resultUrl) return;
+    setSourceName(saved.sourceName || "");
+    setSourceUrl(saved.sourceUrl || "");
+    setIsProcessing(true);
+    cancelRef.current = false;
+    pollRunRef.current += 1;
+    void waitForTaskResult(saved.taskId).catch(() => {});
+  }, []);
 
   useEffect(() => {
     return () => {
       pollRunRef.current += 1;
       cancelRef.current = true;
-      if (activeTaskIdRef.current) {
-        aiGenerationClient.cancelTask(activeTaskIdRef.current).catch(() => {});
-      }
     };
   }, []);
 
@@ -158,6 +171,7 @@ function SubtitleRemovalPage({
     const runId = ++pollRunRef.current;
     setActiveTaskId(taskId);
     setTaskProgress(5);
+    saveToolTaskState("subtitle", { taskId, sourceName, sourceUrl, status: `任务 ${taskId}`, progress: 5 });
 
     await waitForTask(taskId, {
       abortRef: cancelRef,
@@ -170,6 +184,8 @@ function SubtitleRemovalPage({
           setResultUrl(e.resultUrl);
           setStatus("字幕去除完成");
           setTaskProgress(100);
+          clearToolTaskState("subtitle");
+          saveToolTaskState("subtitle", { taskId, resultUrl: e.resultUrl, resultPreview: e.resultUrl, sourceName, sourceUrl, status: "完成", progress: 100 });
         }
       },
     });
@@ -185,6 +201,7 @@ function SubtitleRemovalPage({
     }
     setIsProcessing(false);
     setStatus("已取消");
+    clearToolTaskState("subtitle");
   }, [activeTaskId]);
 
   const handleDownload = async () => {