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/api/serverConnection.ts

@@ -234,6 +234,10 @@ function notifySessionExpired(status: number, response: Response, payload: unkno
   if (/\/auth\//i.test(response.url)) return;
   // SESSION_REPLACED has its own dedicated handling/modal.
   if (getPayloadCode(payload) === "SESSION_REPLACED") return;
+  // If the user never had a session, a 401 is expected — not a session expiry.
+  if (!readStoredSession()) return;
+  // Deliberate early-exit for unauthenticated users — not a real auth failure.
+  if (getPayloadCode(payload) === "NOT_LOGGED_IN") return;
 
   const now = Date.now();
   if (now - lastSessionExpiredEventAt < 1500) return;
@@ -250,6 +254,7 @@ function notifySessionReplaced(status: number, payload: unknown, fallbackMessage
   const message = getPayloadMessage(payload) || fallbackMessage || "您已在别处登录";
   const isSessionReplaced = code === "SESSION_REPLACED" || message.includes("您已在别处登录");
   if (!isSessionReplaced || typeof window === "undefined") return;
+  if (!readStoredSession()) return;
 
   const now = Date.now();
   if (now - lastSessionReplacedEventAt < 1500) return;