fix(gui): keep sidebar controls when collapsed

A closed sidebar previously resolved to a zero-width grid track, clipping
the only toggle and the settings entry with no visible recovery; the closed
preference persisted across reloads, locking the sidebar shut.

- columns.ts maps the closed preference (width 0) to a fixed 60px
  SIDEBAR_COLLAPSED rail through every step of the concession solve;
  closed details still resolve to zero width.
- AppFrame derives data-sidebar-collapsed and the sidebar slot's collapsed
  owner prop from the persisted preference instead of the resolved track
  width, and drops the resize handle while collapsed.
- SidebarRoot reads the owner collapsed prop; the expanded-only body is a
  separate component that unmounts while collapsed (dropping its sessions
  subscription), leaving the expand toggle and Settings in the rail.
- The keyless web smoke gains the ui-sidebar bundle (six real bundles) and
  pins the 60px rail collapse/expand round through the assembled client.

.agents/notes/implemented/bug-fix/2026-07-22-collapsed-sidebar-control-rail.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write
-2026-07-22-collapsed-sidebar-control-rail.md: 27e7d0e18a20b2ea6de8128f9c3518279ec21aca
-2026-07-22-collapsed-sidebar-control-rail.zh.md: bfbb5230f952e49960142bb5ce090dc6753487ec
+2026-07-22-collapsed-sidebar-control-rail.md: 9f244010a1ec14eeafe707aedfffcf7e5bbe7736
+2026-07-22-collapsed-sidebar-control-rail.zh.md: 53007bf717404b151d0a2d1f673c20f111ee8234

.agents/notes/implemented/bug-fix/2026-07-22-collapsed-sidebar-control-rail.md

@@ -6,15 +6,15 @@ English | [中文](2026-07-22-collapsed-sidebar-control-rail.zh.md)
 
 ## Problem
 
-The sidebar close action persisted `open: false`, and the layout mapped that preference to a zero-width grid track. The only sidebar toggle and the settings entry both lived inside that clipped track, so closing the sidebar removed every visible recovery control. Reloading preserved the closed preference and reproduced the lockout.
+The sidebar close action persisted a zero width preference, and the layout mapped that preference to a zero-width grid track. The only sidebar toggle and the settings entry both lived inside that clipped track, so closing the sidebar removed every visible recovery control. Reloading preserved the closed preference and reproduced the lockout.
 
 ## Decision
 
-The layout maps a closed sidebar to the fixed `SIDEBAR_COLLAPSED` width of 60px: one 28px icon control between the sidebar's 16px horizontal paddings. The compact rail participates in the concession solver and retains its right border, while the stored expanded width remains untouched.
+The layout maps a closed sidebar (persisted width `0`) to the fixed `SIDEBAR_COLLAPSED` width of 60px: one 28px icon control between the sidebar's 16px horizontal paddings. The compact rail participates in the concession solver and retains its right border, while the stored expanded width remains untouched.
 
-`AppFrame` marks the sidebar collapsed from the persisted `open` preference rather than from a zero resolved width. It keeps the sidebar slot mounted but removes the resize handle while collapsed.
+`AppFrame` marks the sidebar collapsed from the persisted width preference rather than from the resolved track width, removes the resize handle while collapsed, and passes `collapsed` to the sidebar slot as owner props from the render site.
 
-`SidebarRoot` subscribes to the derived open boolean. Its collapsed render removes the brand, creation controls, search, and session tree from the rendered and accessibility trees; the top control changes to `Expand sidebar`, and the bottom `Settings` control remains in the rail.
+`SidebarRoot` reads the owner `collapsed` prop. Its collapsed render removes the brand, creation controls, search, and session tree from the rendered and accessibility trees — the body component unmounts, dropping its sessions subscription; the top control changes to `Expand sidebar`, and the bottom `Settings` control remains in the rail.
 
 ## Alternatives considered
 

.agents/notes/implemented/bug-fix/2026-07-22-collapsed-sidebar-control-rail.zh.md

@@ -6,15 +6,15 @@ Status: implemented
 
 ## 问题
 
-侧边栏关闭操作会持久化 `open: false`，布局再将该偏好映射为宽度为零的网格轨道。侧边栏唯一的开关与设置入口都位于这个被裁切的轨道内，因此关闭侧边栏会移除所有可见的恢复控件。页面重新加载时仍会读取关闭偏好，从而再次陷入无法恢复的状态。
+侧边栏关闭操作会持久化宽度偏好 `0`，布局再将该偏好映射为宽度为零的网格轨道。侧边栏唯一的开关与设置入口都位于这个被裁切的轨道内，因此关闭侧边栏会移除所有可见的恢复控件。页面重新加载时仍会读取关闭偏好，从而再次陷入无法恢复的状态。
 
 ## 决策
 
-布局将关闭的侧边栏映射为固定的 `SIDEBAR_COLLAPSED` 宽度 60px：在侧边栏两侧各 16px 的水平内边距之间放置一个 28px 的图标控件。紧凑控制栏参与空间收缩求解，并保留右侧边框；已存储的展开宽度保持不变。
+布局将关闭的侧边栏（持久化宽度为 `0`）映射为固定的 `SIDEBAR_COLLAPSED` 宽度 60px：在侧边栏两侧各 16px 的水平内边距之间放置一个 28px 的图标控件。紧凑控制栏参与空间收缩求解，并保留右侧边框；已存储的展开宽度保持不变。
 
-`AppFrame` 根据持久化的 `open` 偏好标记侧边栏是否折叠，而不是根据求解后的宽度是否为零来判断。它让侧边栏插槽保持挂载，但在折叠时移除尺寸调整手柄。
+`AppFrame` 根据持久化的宽度偏好标记侧边栏是否折叠，而不是根据求解后的轨道宽度来判断；折叠时移除尺寸调整手柄，并在渲染点把 `collapsed` 作为 owner props 传给侧边栏插槽。
 
-`SidebarRoot` 订阅派生的布尔型打开状态。折叠状态下的渲染会将品牌标识、创建控件、搜索框和会话树从渲染树与可访问性树中移除；顶部控件变为 `Expand sidebar`，底部的 `Settings` 控件则留在控制栏中。
+`SidebarRoot` 读取 owner 的 `collapsed` 属性。折叠状态下的渲染会将品牌标识、创建控件、搜索框和会话树从渲染树与可访问性树中移除——主体组件卸载，随之退订会话列表；顶部控件变为 `Expand sidebar`，底部的 `Settings` 控件则留在控制栏中。
 
 ## 曾考虑的替代方案