feat(M8): FR-T4/T5/T6/W2/W6/W7 标签页/布局接线——固定标签悬停浮现关闭按钮(T4); tab-store updateScroll+restore恢复滚动位置(T5); tabbarVisible接线App+TitleBar切换按钮(T6/W6); winIsMaximized IPC+最大化/还原图标切换(W2); 极简模式隐藏TabBar(W7); layout-tabs E2E 3 项

apps/desktop/src/renderer/features/tabs/tab-store.ts

@@ -9,6 +9,7 @@ interface TabState {
   closeTab: (id: string) => void;
   setActive: (id: string) => void;
   togglePin: (id: string) => void;
+  updateScroll: (id: string, scrollTop: number) => void; // FR-T5：保存滚动位置
   closeAll: () => void;            // FR-V6: 切库时清空全部标签页
   renamePath: (oldPath: string, newPath: string) => void; // FR-T7: 重命名/移动后同步标签页路径
   activePath: () => string | null;
@@ -46,6 +47,11 @@ export const useTabs = create<TabState>((set, get) => ({
 
   setActive: (id) => { set({ activeId: id }); get().persist(); },
 
+  // FR-T5：更新标签页滚动位置（不触发 persist，避免频繁写入）
+  updateScroll: (id, scrollTop) => {
+    set(s => ({ tabs: s.tabs.map(t => t.id === id ? { ...t, scrollTop } : t) }));
+  },
+
   togglePin: (id) => {
     set(s => {
       const tabs = s.tabs.map(t => t.id === id ? { ...t, pinned: !t.pinned } : t);