fix(frontend): restore terminal tab scroll position

preserve xterm viewport intent when switching terminal tabs so
bottom-pinned sessions stay pinned and manually scrolled sessions
keep their history position

unify viewport restoration across activation, fit, and resize
paths to avoid losing scroll state after terminal reflow

.helloagents/archive/_index.md

@@ -9,6 +9,7 @@
 |--------|------|------|---------|------|------|
 | 202603250317 | ghcr-docker-publish | implementation | workspace-root | ghcr-docker-publish#D001 | ✅完成 |
 | 202603250532 | quickcommands-theme-alignment | implementation | frontend | - | ✅完成 |
+| 202603250547 | terminal-tab-scroll-restore | implementation | frontend | - | ✅完成 |
 | 202603251200 | workspace-workbench-monitor | implementation | frontend, backend | workspace-workbench-monitor#D001 | ✅完成 |
 
 ## 按月归档
@@ -16,6 +17,7 @@
 ### 2026-03
 - [202603250317_ghcr-docker-publish](./2026-03/202603250317_ghcr-docker-publish/) - 新增 GHCR 镜像发布 workflow 并切换 compose 镜像来源
 - [202603250532_quickcommands-theme-alignment](./2026-03/202603250532_quickcommands-theme-alignment/) - 统一快捷指令视图按钮主题适配，移除残留硬编码 hover 色值
+- [202603250547_terminal-tab-scroll-restore](./2026-03/202603250547_terminal-tab-scroll-restore/) - 修复终端标签切换后的贴底/历史滚动恢复逻辑
 - [202603251200_workspace-workbench-monitor](./2026-03/202603251200_workspace-workbench-monitor/) - `/workspace` 改为三栏 Workbench 布局，并新增开机累计流量监控
 
 ## 结果状态说明