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.

packages/client/ui-layout/tests/app-frame.spec.tsx

@@ -15,6 +15,7 @@ import { act, cleanup, render } from '@testing-library/react'
 import { useSyncExternalStore } from 'react'
 import { AppFrame } from '@deepseek-ai/dsh-client-ui-layout/src/client/AppFrame.tsx'
 import type { AppFrameProps } from '@deepseek-ai/dsh-client-ui-layout/src/client/AppFrame.tsx'
+import { SIDEBAR_COLLAPSED } from '@deepseek-ai/dsh-client-ui-layout/src/client/columns.ts'
 import { createLayoutStore } from '@deepseek-ai/dsh-client-ui-layout/src/client/stores.ts'
 
 // Session-mode switch for the SessionProvider stub prop.
@@ -175,6 +176,16 @@ describe('AppFrame', () => {
     expect(frame.hasAttribute('data-details-collapsed')).toBe(true)
   })
 
+  it('closed sidebar keeps its compact rail with mounted slot content and collapsed owner props', () => {
+    const { frame, instance, slotCalls, getByTestId } = mountFrame()
+    act(() => { instance.actions.toggleSidebar() })
+    expect(tracks(frame)).toEqual([SIDEBAR_COLLAPSED, 360])
+    expect(getByTestId('sidebar-content')).toBeTruthy()
+    expect(frame.hasAttribute('data-sidebar-collapsed')).toBe(true)
+    const lastSidebarCall = slotCalls.filter((c) => c.key === 'sidebar').at(-1)!
+    expect(lastSidebarCall.props).toEqual({ collapsed: true, width: SIDEBAR_COLLAPSED })
+  })
+
   it('viewport shrink triggers the concession chain via ResizeObserver', () => {
     const { frame } = mountFrame()
     frameWidth = 1250

packages/client/ui-layout/tests/columns.spec.ts

@@ -1,7 +1,7 @@
 import { describe, expect, it } from 'vitest'
 import {
   CENTER_MIN, clampWidth, computeColumns,
-  DETAILS_DEFAULT, DETAILS_MIN, SIDEBAR_DEFAULT, SIDEBAR_MIN,
+  DETAILS_DEFAULT, DETAILS_MIN, SIDEBAR_COLLAPSED, SIDEBAR_DEFAULT, SIDEBAR_MIN,
 } from '@deepseek-ai/dsh-client-ui-layout/src/client/columns.ts'
 
 // Numeric preference form (0 = closed); helpers keep the scenario names readable.
@@ -22,8 +22,9 @@ describe('computeColumns', () => {
     expect(cols).toEqual({ sidebar: 300, center: 1920 - 300 - 360, details: 360 })
   })
 
-  it('closed panels contribute zero width', () => {
-    expect(computeColumns(1920, closed(300), closed(360))).toEqual({ sidebar: 0, center: 1920, details: 0 })
+  it('closed sidebar keeps its compact rail while closed details contribute zero width', () => {
+    expect(computeColumns(1920, closed(300), closed(360)))
+      .toEqual({ sidebar: SIDEBAR_COLLAPSED, center: 1920 - SIDEBAR_COLLAPSED, details: 0 })
   })
 
   it('preferences beyond the clamp range are clamped before solving', () => {
@@ -70,10 +71,14 @@ describe('computeColumns', () => {
   })
 
   it('sidebar-closed narrow window: details concedes then auto-closes', () => {
-    const fits = computeColumns(DETAILS_MIN + CENTER_MIN, closed(300), open(DETAILS_DEFAULT))
-    expect(fits).toEqual({ sidebar: 0, center: CENTER_MIN, details: DETAILS_MIN })
-    const starved = computeColumns(DETAILS_MIN + CENTER_MIN - 1, closed(300), open(DETAILS_DEFAULT))
-    expect(starved).toEqual({ sidebar: 0, center: DETAILS_MIN + CENTER_MIN - 1, details: 0 })
+    const fits = computeColumns(SIDEBAR_COLLAPSED + DETAILS_MIN + CENTER_MIN, closed(300), open(DETAILS_DEFAULT))
+    expect(fits).toEqual({ sidebar: SIDEBAR_COLLAPSED, center: CENTER_MIN, details: DETAILS_MIN })
+    const starved = computeColumns(SIDEBAR_COLLAPSED + DETAILS_MIN + CENTER_MIN - 1, closed(300), open(DETAILS_DEFAULT))
+    expect(starved).toEqual({
+      sidebar: SIDEBAR_COLLAPSED,
+      center: DETAILS_MIN + CENTER_MIN - 1,
+      details: 0,
+    })
   })
 
   it('tiny viewport: both panels yield everything to center', () => {
@@ -93,9 +98,9 @@ describe('computeColumns', () => {
 })
 
 describe('computeColumns — degenerate viewports', () => {
-  it('sidebar closed and viewport below CENTER_MIN: details auto-closes, center takes all', () => {
-    // Reaches step 4's re-solve with s0 = 0 (the closed-sidebar arm).
+  it('sidebar closed and viewport below CENTER_MIN: details auto-closes, center takes the rest', () => {
+    // Reaches step 4's re-solve with the compact rail as the sidebar floor.
     expect(computeColumns(500, closed(300), open(DETAILS_DEFAULT)))
-      .toEqual({ sidebar: 0, center: 500, details: 0 })
+      .toEqual({ sidebar: SIDEBAR_COLLAPSED, center: 500 - SIDEBAR_COLLAPSED, details: 0 })
   })
 })