Merge origin/master into codex/figma-context-injection-row

.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.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 .agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.md
-2026-07-29-web-details-session-lifecycle.md: d9e0255768f165bed0631b9324e971b57ec7dcae
-2026-07-29-web-details-session-lifecycle.zh.md: 09452ba80ff240ddca76df239b40ea661566f8e2
+2026-07-29-web-details-session-lifecycle.md: cc1501440d50cb560291e416a0f2b0292e08e1c8
+2026-07-29-web-details-session-lifecycle.zh.md: 1102530f288359ebc5fb04a36c2b813da41e1318

.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.md

@@ -10,9 +10,9 @@ The details entry is Session-scoped, but its preferred grid width is root-scoped
 
 ## Decision
 
-`AppFrame` reads the current Session id and its `blank` summary flag from the authoritative Session projection. It records the last non-blank selected id only when that Session can own details, so hero and other unselected states neither trigger closure nor replace the last Session owner; their rendered details track derives as zero without changing the stored preference. The first Session keeps the default details width; returning to the same Session restores its current width; selecting a different Session closes the root-scoped details preference through the layout store before paint. The per-Session chat selection remains owned by the session-scoped store described by the [slot system standard](../architecture/2026-07-22-slot-type-chain-implementation.md).
+`AppFrame` reads the current Session id and its `blank` summary flag from the authoritative Session projection. It records the last non-blank selected id only when that Session can own details, so hero and other unselected states neither trigger closure nor replace the last Session owner; their rendered details track derives as zero without changing the stored preference. The first Session preserves the layout store's initial preference, whose [visibility default is now closed](2026-07-30-web-details-default-closed.md); returning to the same Session restores its current width, and selecting a different Session closes the root-scoped details preference through the layout store before paint. The per-Session chat selection remains owned by the session-scoped store described by the [slot system standard](../architecture/2026-07-22-slot-type-chain-implementation.md).
 
-The layout store is transient and starts details at its default width. It neither reads nor writes `localStorage`, so reload resets both panel widths and needs no Session-baseline exception. Manual close and reopen inside one unchanged Session retain their existing behavior. The lifecycle effect changes neither the [Workspace-owned New Session flow](../feature/2026-07-25-workspace-ui-product-flow.md), composer drafts, Session navigation, nor concession-chain resizing.
+The layout store is transient and starts details closed. It neither reads nor writes `localStorage`, so reload restores the sidebar default and details closed and needs no Session-baseline exception. Manual close and reopen inside one unchanged Session retain their existing behavior. The lifecycle effect changes neither the [Workspace-owned New Session flow](../feature/2026-07-25-workspace-ui-product-flow.md), composer drafts, Session navigation, nor concession-chain resizing.
 
 ## Alternatives considered
 
@@ -26,4 +26,4 @@ The layout store is transient and starts details at its default width. It neithe
 
 ## Consequences
 
-Details is open by default, including when the first Session materializes. Switching to a different Session forgets the dragged details width because close writes zero and reopen uses the contract default. Unselected states derive a zero rendered track while leaving the preferred geometry unchanged; returning to the same Session through one of those states restores its width. Reload forgets sidebar and details geometry. The layout behavior test covers initial defaults, first materialization, direct and hero-mediated Session switches, same-Session return, and the absence of layout storage; the keyless browser e2e drives the same owner transitions through the shipped composition while checking the full grid track and browser errors.
+Details starts closed, including when the first Session materializes. An explicit open action uses the contract default width. Switching to a different Session forgets a dragged details width because close writes zero and reopen uses that default. Unselected states derive a zero rendered track while leaving the preferred geometry unchanged; returning to the same Session through one of those states restores its width. Reload forgets sidebar geometry and restores details closed. The layout behavior test covers initial defaults, first materialization, direct and hero-mediated Session switches, same-Session return, and the absence of layout storage; the keyless browser e2e drives the same owner transitions through the shipped composition while checking the full grid track and browser errors.

.agents/notes/implemented/bug-fix/2026-07-29-web-details-session-lifecycle.zh.md

@@ -10,9 +10,9 @@ Status: implemented
 
 ## 决策
 
-`AppFrame` 从权威会话投影读取当前会话 id 及其摘要中的 `blank` 标志。它只在该会话能够拥有详情时记录最后一个选中的非 blank 会话 id，因此 hero 和其他未选中状态既不会触发关闭，也不会替换最后一个会话 owner；这些状态下，详情栏轨道的渲染宽度派生为零，但存储的首选宽度不变。首个会话保留详情栏的默认宽度；返回同一会话时恢复其当前宽度；选择不同会话时，系统会先通过布局 store 关闭根作用域存储的详情栏首选宽度，再进行绘制。逐会话的聊天选中项继续由 [slot 体系标准](../architecture/2026-07-22-slot-type-chain-implementation.md)所述的会话作用域 store 拥有。
+`AppFrame` 从权威会话投影读取当前会话 id 及其摘要中的 `blank` 标志。它只在该会话能够拥有详情时记录最后一个选中的非 blank 会话 id，因此 hero 和其他未选中状态既不会触发关闭，也不会替换最后一个会话 owner；这些状态下，详情栏轨道的渲染宽度派生为零，但存储的首选宽度不变。首个会话保留布局 store 的初始首选值，该值的[可见性默认设置现为关闭](2026-07-30-web-details-default-closed.md)；返回同一会话时恢复其当前宽度；选择不同会话时，系统会先通过布局 store 关闭根作用域存储的详情栏首选宽度，再进行绘制。逐会话的聊天选中项继续由 [slot 体系标准](../architecture/2026-07-22-slot-type-chain-implementation.md)所述的会话作用域 store 拥有。
 
-布局 store 是瞬时状态，详情栏以默认宽度启动。它既不读取也不写入 `localStorage`，因此重新加载会重置两个面板的宽度，无需会话基线例外。在同一个未变化的会话内手动关闭和重新打开详情栏，仍保持原有行为。该生命周期 effect 不改变 [Workspace 拥有的 New Session 动线](../feature/2026-07-25-workspace-ui-product-flow.md)、composer 草稿、会话导航或让步链缩放。
+布局 store 是瞬时状态，详情栏在启动时保持关闭。它既不读取也不写入 `localStorage`，因此重新加载会恢复侧边栏默认值，并使详情栏保持关闭，无需会话基线例外。在同一个未变化的会话内手动关闭和重新打开详情栏，仍保持原有行为。该生命周期 effect 不改变 [Workspace 拥有的 New Session 动线](../feature/2026-07-25-workspace-ui-product-flow.md)、composer 草稿、会话导航或让步链缩放。
 
 ## 考虑过的替代方案
 
@@ -26,4 +26,4 @@ Status: implemented
 
 ## 后果
 
-详情栏默认打开，首次会话物化时亦然。切换到不同会话会忘记拖动后的详情宽度，因为关闭操作会写入零值，重新打开时则使用契约默认值。未选中状态会将轨道的渲染宽度派生为零，同时保持首选几何信息不变；经由这些状态返回同一会话时，会恢复其宽度。重新加载会忘记侧边栏与详情栏的几何信息。布局行为测试覆盖初始默认值、首次物化、直接及经 hero 中转的会话切换、返回同一会话，以及不存在布局存储的情况；无密钥浏览器 e2e 则通过已交付的组合驱动相同的 owner 过渡，同时检查完整网格轨道和浏览器错误。
+详情栏在启动时保持关闭，首次会话物化时亦然。显式打开操作会使用契约默认宽度。切换到不同会话会忘记拖动后的详情宽度，因为关闭操作会写入零值，重新打开时则使用该默认值。未选中状态会将轨道的渲染宽度派生为零，同时保持首选几何信息不变；经由这些状态返回同一会话时，会恢复其宽度。重新加载会忘记侧边栏几何信息，并使详情栏恢复关闭状态。布局行为测试覆盖初始默认值、首次物化、直接及经 hero 中转的会话切换、返回同一会话，以及不存在布局存储的情况；无密钥浏览器 e2e 则通过已交付的组合驱动相同的 owner 过渡，同时检查完整网格轨道和浏览器错误。

.agents/notes/implemented/bug-fix/2026-07-30-web-details-default-closed.i18n.yaml

@@ -0,0 +1,6 @@
+# Bilingual-pair consistency record (docs/i18n/README.md): the git blob hash of each
+# 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 .agents/notes/implemented/bug-fix/2026-07-30-web-details-default-closed.md
+2026-07-30-web-details-default-closed.md: 658b6fc2c18dc67d8759bec78997f32dcba27914
+2026-07-30-web-details-default-closed.zh.md: 5a1d0e4713e47ce3bc0cc68fa4c4f5f8c94c945f

.agents/notes/implemented/bug-fix/2026-07-30-web-details-default-closed.md

@@ -0,0 +1,27 @@
+# Agent Note: Web details default closed
+
+Status: implemented
+
+English | [中文](2026-07-30-web-details-default-closed.zh.md)
+
+## Problem
+
+The transient layout store initialized details to its 360px contract width. The first connected Session and every full reload therefore reserved a right column before the user selected any detail content. Chat tool rows deliberately remain inline and do not open details, while Trajectory rows open the panel when an event is selected, so an open layout default did not represent an active detail selection.
+
+## Decision
+
+The layout store initializes details to zero while retaining the existing 360px contract default for `openDetails()`. `AppFrame` keeps the details slot mounted at zero width, so an explicit entry point such as Trajectory event selection can open the panel without remounting its subtree. The [Session ownership lifecycle](2026-07-29-web-details-session-lifecycle.md) remains authoritative: unselected surfaces derive zero width without taking ownership, returning to the same Session preserves an explicitly opened width, and selecting a different Session closes it.
+
+Panel geometry remains transient. No browser storage key is introduced, and reload restores the sidebar default while details returns to zero. Component tests pin the store default, mounted zero-width slot, drag and concession behavior after explicit opening, and Session ownership transitions. The keyless shipped-composition regression pins the closed first Session, reload, new-session surface, and subsequent Session selections.
+
+## Alternatives considered
+
+**Persist the last open or closed preference.** Rejected because reload should have a deterministic closed baseline, and persisting geometry would reintroduce stale viewing state across browser sessions.
+
+**Keep details open until Chat receives a replacement selection gesture.** Rejected because empty space is not useful detail content. Chat's inline tool-row interaction and any future detail-selection gesture are separate product decisions.
+
+**Remove the details column and layout service.** Rejected because Trajectory already opens event details through this seam, and keeping the mounted slot preserves that working interaction.
+
+## Consequences
+
+New, restored, and reloaded Sessions use the full center area until an explicit details action opens the right column. Trajectory event selection can still open details at 360px and its close control returns the track to zero; Chat tool rows remain geometry-inert. Switching to another Session closes an opened panel, and no panel state survives reload.

.agents/notes/implemented/bug-fix/2026-07-30-web-details-default-closed.zh.md

@@ -0,0 +1,27 @@
+# Agent Note: Web 详情栏默认关闭
+
+Status: implemented
+
+[English](2026-07-30-web-details-default-closed.md) | 中文
+
+## 问题
+
+瞬时布局 store 原本将详情栏初始化为 360px 的契约宽度。因此，首个已连接会话以及每次完整重新加载都会在用户选择任何详情内容之前预留右侧栏。Chat 工具行有意保持内联，不会打开详情栏；Trajectory 行则会在选中事件时打开详情栏。因此，布局默认打开并不表示存在有效的详情选中项。
+
+## 决策
+
+布局 store 将详情栏初始化为零，同时保留 `openDetails()` 现有的 360px 契约默认宽度。`AppFrame` 仍以零宽度挂载详情 slot，因此 Trajectory 事件选择等显式入口可以打开详情栏，而无需重新挂载其子树。[会话所有权生命周期](2026-07-29-web-details-session-lifecycle.md)仍是权威契约：未选中表面会派生零宽度而不取得所有权；返回同一会话时会保留显式打开后的宽度；选择不同会话时则会关闭详情栏。
+
+面板几何信息仍是瞬时状态。系统不新增浏览器存储键；重新加载会恢复侧边栏默认值，并使详情栏回到零宽度。组件测试固定验证 store 默认值、保持挂载的零宽度 slot、显式打开后的拖动与让步行为，以及会话所有权过渡。无密钥的已交付组合回归测试固定验证首个会话保持关闭、重新加载、New Session 表面和后续会话选择。
+
+## 考虑过的替代方案
+
+**持久化最后一次打开或关闭的首选状态。** 之所以否决：重新加载必须具有确定的关闭基线，而持久化几何信息会在浏览器会话之间重新引入陈旧的查看状态。
+
+**在 Chat 获得替代性的选择手势前保持详情栏打开。** 之所以否决：空白区域不是有用的详情内容。Chat 的内联工具行交互与未来可能增加的详情选择手势属于彼此独立的产品决策。
+
+**移除详情栏和布局服务。** 之所以否决：Trajectory 已经通过该服务边界打开事件详情；继续挂载该 slot 可以保留这一正常工作的交互。
+
+## 后果
+
+新建、恢复和重新加载的会话会使用完整的中央区域，直至显式详情操作打开右侧栏。Trajectory 事件选择仍可将详情栏打开至 360px，其关闭控件会使轨道回到零；Chat 工具行仍不改变几何信息。切换到其他会话会关闭已打开的详情栏，并且任何面板状态都不会在重新加载后保留。

apps/web/tests/code-mode-round.e2e.ts

@@ -118,14 +118,14 @@ describe('web e2e: Code Mode round renders nested sub-calls', () => {
     expect(await nest.locator('[data-state="error"]').count()).toBeGreaterThanOrEqual(1)
   }, 60_000)
 
-  it.skipIf(MODE === 'record')('a bash sub-row click leaves the default details panel open', async () => {
+  it.skipIf(MODE === 'record')('a bash sub-row click leaves the default details panel closed', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-code-mode-details'))
     const nest = page.locator('[data-subcalls]').first()
     const frame = page.locator('[style*="grid-template-columns"]').first()
-    expect(await frame.getAttribute('data-details-collapsed')).toBeNull()
+    expect(await frame.getAttribute('data-details-collapsed')).toBe('true')
     await nest.locator('[data-sample="bash-global"]').first().click()
-    // Tool rows do not drive layout geometry; the Session's default panel stays open.
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBeNull()
+    // Tool rows do not drive layout geometry; the Session's default panel stays closed.
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe('true')
   })
 
   it.skipIf(MODE === 'record')('matches the conversation aria golden with stable anchors', async () => {

apps/web/tests/details-session-lifecycle.e2e.ts

@@ -1,12 +1,14 @@
-// Keyless browser regression for the details column's Session ownership.
-// The shipped composition retains geometry through unselected states and closes it only when a different Session takes ownership.
+// Keyless browser regression for the details column's default visibility and Session ownership.
+// The shipped composition starts closed after selection and reload, retains an explicitly opened width through
+// unselected states, and closes it only when a different Session takes ownership.
 import { readFile } from 'node:fs/promises'
 import { fileURLToPath } from 'node:url'
 import type { Browser, Page } from 'playwright'
 import { chromium } from 'playwright'
 import { afterAll, beforeAll, describe, expect, it, onTestFailed } from 'vitest'
 import {
-  fixtureUserPrompts, launchWebScaffold, seedSession, watchConsole, webSnapshotMode, type WebScaffold,
+  acknowledgeReloadConnectionLoss, fixtureUserPrompts, launchWebScaffold, seedSession, watchConsole,
+  webSnapshotMode, type WebScaffold,
 } from './scaffold.ts'
 import { connectFreshWorkspace, newEnglishPage, saveFailureShot } from './support.ts'
 
@@ -52,7 +54,7 @@ describe.skipIf(MODE === 'record')('web e2e: details panel follows the current S
     await scaffold?.close()
   })
 
-  it('retains geometry through hero and closes it for a different Session', async () => {
+  it('starts and reloads closed, then stays closed across Session ownership changes', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-details-session-lifecycle'))
     const settled = scaffold.whenTurnSettled()
     const input = page.locator('textarea').first()
@@ -61,10 +63,18 @@ describe.skipIf(MODE === 'record')('web e2e: details panel follows the current S
     await settled
     await page.getByText('LIGHTHOUSE', { exact: true }).waitFor({ timeout: 15_000 })
 
-    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(360)
-    expect(await page.getByText('详情', { exact: true }).count()).toBe(1)
+    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(0)
+    expect(await page.getByText('详情', { exact: true }).isVisible()).toBe(false)
 
-    await page.getByRole('button', { name: 'New session', exact: true }).last().click()
+    const warningStart = tripwire.warnings.length
+    await page.reload({ waitUntil: 'load' })
+    acknowledgeReloadConnectionLoss(tripwire, warningStart)
+    await appFrame(page).waitFor({ timeout: 30_000 })
+    await page.getByText('LIGHTHOUSE', { exact: true }).waitFor({ timeout: 15_000 })
+    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(0)
+    expect(await page.getByText('详情', { exact: true }).isVisible()).toBe(false)
+
+    await page.getByRole('button', { name: /^(?:New session|新.*会话)$/ }).last().click()
     await page.getByText("Let's start building", { exact: false }).waitFor({ timeout: 15_000 })
     await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(0)
     expect(await page.getByText('详情', { exact: true }).isVisible()).toBe(false)
@@ -72,8 +82,8 @@ describe.skipIf(MODE === 'record')('web e2e: details panel follows the current S
     const original = page.locator('[role=treeitem]').filter({ hasText: 'Reply with the single word' }).first()
     await original.click()
     await page.getByText('LIGHTHOUSE', { exact: true }).waitFor({ timeout: 15_000 })
-    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(360)
-    expect(await page.getByText('详情', { exact: true }).count()).toBe(1)
+    await expect.poll(() => detailsTrack(page), { timeout: 5_000 }).toBe(0)
+    expect(await page.getByText('详情', { exact: true }).isVisible()).toBe(false)
 
     const ungrouped = page.getByText('Ungrouped', { exact: true })
     const ungroupedRow = ungrouped.locator('..').locator('..')

apps/web/tests/navigation-panes.e2e.ts

@@ -173,24 +173,24 @@ describe('web e2e: navigation & panes over a rich seeded session', () => {
     await expect.poll(() => page.locator('tr[data-timeline-focus]').count(), { timeout: 10_000 }).toBe(0)
   }, 60_000)
 
-  it.skipIf(MODE === 'record')('bash and file-path rows leave the default details column open', async () => {
+  it.skipIf(MODE === 'record')('bash and file-path rows leave the default details column closed', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-navigation-details'))
     await page.getByRole('tab', { name: 'Chat' }).click()
     const bashRow = page.locator('[data-sample="bash-global"]').first()
     await bashRow.waitFor({ timeout: 15_000 })
     const frame = page.locator('[style*="grid-template-columns"]').first()
-    expect(await frame.getAttribute('data-details-collapsed')).toBeNull()
+    expect(await frame.getAttribute('data-details-collapsed')).toBe('true')
     await bashRow.click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBeNull()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe('true')
     // The card's own controls are outside the summary row and must not open
     // details either — the terminal card is read in place.
     await page.locator('[data-sample="bash-global"] ~ [data-terminal] [class*="_copyButton_"]').first().click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBeNull()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe('true')
     // Read summaries are host-open file links; they also must not open details.
     const fileLink = page.locator('[data-variant="read"] button').first()
     await fileLink.waitFor({ timeout: 10_000 })
     await fileLink.click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBeNull()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe('true')
   }, 60_000)
 
   it.skipIf(MODE === 'record')('renders the bash row as a terminal card in the real browser', async () => {

apps/web/tests/seeded-history.e2e.ts

@@ -218,9 +218,9 @@ describe('web e2e: seeded history renders through cold resume', () => {
     const fileLink = page.locator('[data-variant="read"] button').first()
     await fileLink.waitFor({ timeout: 10_000 })
     const frame = page.locator('[style*="grid-template-columns"]').first()
-    expect(await frame.getAttribute('data-details-collapsed')).toBeNull()
+    expect(await frame.getAttribute('data-details-collapsed')).toBe('true')
     await fileLink.click()
-    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBeNull()
+    await expect.poll(() => frame.getAttribute('data-details-collapsed'), { timeout: 5_000 }).toBe('true')
     // Path label survives from the recorded args (a.txt).
     await expect.poll(() => page.getByText('a.txt', { exact: false }).count(), { timeout: 5_000 }).toBeGreaterThan(0)
   })

apps/web/tests/smoke-real.e2e.ts

@@ -454,7 +454,7 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY || notReady.length > 0)('web smoke
     await screen(page, '07-back-to-chat')
   })
 
-  it('5 bash differential rendering: tool row click leaves the default details column open', async () => {
+  it('5 bash differential rendering: tool row click leaves the default details column closed', async () => {
     onTestFailed(() => saveFailureShot(page, 'w5-tool-details'))
     const input = page.locator('textarea').first()
     await input.fill('请用 bash 工具运行命令 echo w5marker 然后告诉我结果')
@@ -466,11 +466,11 @@ describe.skipIf(!process.env.DEEPSEEK_API_KEY || notReady.length > 0)('web smoke
     const toolRow = page.locator('[data-sample="bash-global"]')
     await toolRow.waitFor({ timeout: 120_000 })
     await screen(page, '08-bash-round')
-    expect(await detailsTrack(page)).toBe(360)
+    expect(await detailsTrack(page)).toBe(0)
     await toolRow.click()
-    // Tool rows no longer drive layout.openDetails; the default column stays open.
-    expect(await detailsTrack(page)).toBe(360)
-    await screen(page, '09-details-open')
+    // Tool rows no longer drive layout.openDetails; the default column stays closed.
+    expect(await detailsTrack(page)).toBe(0)
+    await screen(page, '09-details-closed')
   }, 150_000)
 
   it('6 sidebar drag widens the column and resets across reload', async () => {

packages/client/ui-layout/README.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 packages/client/ui-layout/README.md
-README.md: 9354f4b79f7b1af7d8a20a295e77913ff443c2e4
-README.zh.md: c949236557e7eb3eed0c698566fb5aa9e9cdd18a
+README.md: 0e92958c9b088071ab58f7e87e8af68f6c2df68d
+README.zh.md: 0fb3b1cd85bbf6e070a2a1dd01b25981e5990df0

packages/client/ui-layout/README.md

@@ -4,7 +4,7 @@ English | [中文](README.zh.md)
 
 Shell plugin: three-column AppFrame (drag handles and concession chain) plus the `ctx.layout` panel-geometry service; it registers into the runtime-owned `root` slot and declares `sidebar`, `conversation`, `details`, and `conversation.empty`. The sidebar is fixed-width (only details shrinks, then auto-closes); a closed sidebar retains a 56px control rail while details closes to zero width. The package also seats the theme presenter: it consumes resolved `ctx.theme` snapshots and projects them onto the document (`html { color-scheme }` for native UA chrome, `body[data-ds-dark-theme]` from the active color scheme, plus the theme's alias tokens as inline variables on body).
 
-AppFrame always mounts the conversation and details columns; a connected Session renders through `SessionProvider`. The transient layout store starts both panels at their default widths and never reads or writes `localStorage`. Hero and other unselected states derive a zero rendered details width without changing that stored preference. AppFrame retains the last non-blank Session id across those states: the first Session opens at the default width, returning to the same Session restores its unchanged width, and selecting a different Session closes details before paint. The conversation owner share is empty, while the sidebar owner share contains only `collapsed` and `width`; registrants obtain business data from standard hooks and actions from their own inject faces.
+AppFrame always mounts the conversation and details columns; a connected Session renders through `SessionProvider`. The transient layout store starts the sidebar at its default width and details closed, and it never reads or writes `localStorage`. Hero and other unselected states also derive a zero rendered details width without changing that stored preference. AppFrame retains the last non-blank Session id across those states: the first Session remains closed, an explicit details action opens the contract default width, returning to the same Session restores its unchanged width, and selecting a different Session closes details before paint. The conversation owner share is empty, while the sidebar owner share contains only `collapsed` and `width`; registrants obtain business data from standard hooks and actions from their own inject faces.
 
 The `/client` export surface is the plugin body (`apply`/`inject`), `LayoutService`, and the four owner-share interfaces. AppFrame, the panel store, and the concession solver remain package-internal; tests import internals through `/src`.
 
@@ -18,6 +18,6 @@ None; this package neither assembles nor sends a provider request.
 
 ## Known Limitations and Deferred Work
 
-- **Panel geometry is transient** — reload restores both panels to their defaults; switching between distinct Session ids closes details and forgets its dragged width, while unselected surfaces render details at zero width without modifying geometry.
+- **Panel geometry is transient** — reload restores the sidebar default and details closed; switching between distinct Session ids also closes details and forgets its dragged width, while unselected surfaces render details at zero width without modifying geometry.
 - **Concession-chain auto-close derives a zero width without touching the preferred width** — the panel restores itself when the window widens; consumers must not read the stored details width as the rendered truth.
 - **Scroll anchoring during squeeze reflow is not implemented** — deferred with the virtualized-list project.

packages/client/ui-layout/README.zh.md

@@ -4,7 +4,7 @@
 
 外壳插件：三栏 AppFrame（拖动手柄与让步链）加 `ctx.layout` 面板几何服务；它注册到运行时拥有的 `root` slot，并声明 `sidebar`、`conversation`、`details` 和 `conversation.empty`。侧边栏宽度固定（只会收缩详情栏，然后将其自动关闭）；关闭的侧边栏仍保留 56px 控制轨道，详情栏则关闭到零宽度。该包还提供主题呈现器：它消费解析后的 `ctx.theme` 快照，并将其投影到 document（用 `html { color-scheme }` 驱动原生 UA 控件，依据当前配色方案设置 `body[data-ds-dark-theme]`，并将主题的别名 token 设为 body 上的内联变量）。
 
-AppFrame 始终挂载会话栏和详情栏；已连接 Session 通过 `SessionProvider` 渲染。布局 store 是瞬时状态，两个面板均以默认宽度启动，且从不读写 `localStorage`。hero 和其他未选中状态会将详情栏的渲染宽度派生为零，但不会改变存储的首选宽度。AppFrame 会跨越这些状态保留最后一个非 blank 会话 id：首个会话以默认宽度打开；返回同一会话时恢复其未改变的宽度；选择不同会话时，详情栏会在绘制前关闭。会话 owner share 为空，侧边栏 owner share 只包含 `collapsed` 和 `width`；注册方通过标准钩子获取业务数据，并从各自的 inject 表层获取操作。
+AppFrame 始终挂载会话栏和详情栏；已连接 Session 通过 `SessionProvider` 渲染。布局 store 是瞬时状态，侧边栏以默认宽度启动，详情栏则保持关闭，且该 store 从不读写 `localStorage`。hero 和其他未选中状态也会将详情栏的渲染宽度派生为零，但不会改变存储的首选宽度。AppFrame 会跨越这些状态保留最后一个非 blank 会话 id：首个会话保持关闭；显式打开详情栏的操作会使用契约默认宽度；返回同一会话时恢复其未改变的宽度；选择不同会话时，详情栏会在绘制前关闭。会话 owner share 为空，侧边栏 owner share 只包含 `collapsed` 和 `width`；注册方通过标准钩子获取业务数据，并从各自的 inject 表层获取操作。
 
 `/client` 导出表层包含插件主体（`apply`／`inject`）、`LayoutService` 和四个 owner-share 接口。AppFrame、面板 store 与让步求解器仍属于包内部；测试通过 `/src` 导入内部实现。
 
@@ -18,6 +18,6 @@ AppFrame 始终挂载会话栏和详情栏；已连接 Session 通过 `SessionPr
 
 ## 已知限制与暂缓事项
 
-- **面板几何信息是瞬时状态**：重新加载会将两个面板恢复为默认值；在不同会话 id 之间切换会关闭详情栏，并忘记拖动后的宽度，而未选中表面会以零宽度渲染详情栏，但不会修改几何信息。
+- **面板几何信息是瞬时状态**：重新加载会恢复侧边栏默认值，并使详情栏保持关闭；在不同会话 id 之间切换同样会关闭详情栏，并忘记拖动后的宽度，而未选中表面会以零宽度渲染详情栏，但不会修改几何信息。
 - **让步链自动关闭通过推导零宽度实现，不会改动首选宽度**：窗口变宽时面板会自行恢复；消费方禁止把 store 中的详情宽度当作实际渲染状态。
 - **挤压重排期间尚未实现滚动锚定**：与虚拟化列表项目一并暂缓。

packages/client/ui-layout/src/client/stores.ts

@@ -38,7 +38,7 @@ type LayoutActions = {
  */
 export function createLayoutStore(): EngineStoreHandle<LayoutState, LayoutActions>  {
   const handle = defineStore({
-    init: (): LayoutState => ({ sidebar: SIDEBAR_DEFAULT, details: DETAILS_DEFAULT }),
+    init: (): LayoutState => ({ sidebar: SIDEBAR_DEFAULT, details: 0 }),
     actions: {
       setSidebar: (d, px: number) => { d.sidebar = clampWidth(px, SIDEBAR_MIN, SIDEBAR_MAX) },
       setDetails: (d, px: number) => { d.details = clampWidth(px, DETAILS_MIN, DETAILS_MAX) },

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

@@ -139,7 +139,7 @@ afterEach(() => {
 describe('AppFrame', () => {
   it('renders three tracks from store state', () => {
     const { frame } = mountFrame()
-    expect(tracks(frame)).toEqual([280, 360])
+    expect(tracks(frame)).toEqual([280, 0])
   })
 
   it('renders the session pair with empty owner shares (sessionId is framework-standard)', () => {
@@ -174,6 +174,9 @@ describe('AppFrame', () => {
 
   it('ignores unselected states and closes only when the Session id changes', () => {
     const { frame, instance, rerenderFrame } = mountFrame()
+    expect(tracks(frame)).toEqual([280, 0])
+
+    act(() => { instance.actions.openDetails() })
     expect(tracks(frame)).toEqual([280, 360])
 
     selectedSession.current = 's-next' as SessionId
@@ -200,15 +203,15 @@ describe('AppFrame', () => {
     expect(tracks(frame)).toEqual([280, 0])
   })
 
-  it('keeps the default details width when the first Session materializes', () => {
+  it('keeps details closed when the first Session materializes', () => {
     selectedSession.current = undefined
     const { frame, instance, rerenderFrame } = mountFrame()
     expect(tracks(frame)).toEqual([280, 0])
-    expect(instance.getSnapshot().details).toBe(360)
+    expect(instance.getSnapshot().details).toBe(0)
 
     selectedSession.current = 's-first' as SessionId
     act(() => { rerenderFrame() })
-    expect(tracks(frame)).toEqual([280, 360])
+    expect(tracks(frame)).toEqual([280, 0])
   })
 
   it('sidebar slot receives live concession output as owner props', () => {
@@ -224,7 +227,8 @@ describe('AppFrame', () => {
   })
 
   it('details drag widens leftward (negative dx grows the panel)', () => {
-    const { frame } = mountFrame()
+    const { frame, instance } = mountFrame()
+    act(() => { instance.actions.openDetails() })
     const handles = frame.querySelectorAll('[class*="handle"]')
     drag(handles[1]!, 1560, 1500)
     expect(tracks(frame)[1]).toBe(420)
@@ -233,6 +237,7 @@ describe('AppFrame', () => {
   it('drag base is the rendered (concession-clamped) width, not the preference', () => {
     frameWidth = 1250 // step-2 squeeze: details renders 330 while preference is 360
     const { frame, instance } = mountFrame()
+    act(() => { instance.actions.openDetails() })
     expect(tracks(frame)).toEqual([280, 330])
     const handles = frame.querySelectorAll('[class*="handle"]')
     drag(handles[1]!, 920, 930) // shrink by 10 from the rendered width
@@ -240,8 +245,7 @@ describe('AppFrame', () => {
   })
 
   it('details column stays mounted at zero width', () => {
-    const { frame, instance, getByTestId } = mountFrame()
-    act(() => { instance.actions.closeDetails() })
+    const { frame, getByTestId } = mountFrame()
     expect(tracks(frame)).toEqual([280, 0])
     expect(getByTestId('details-content')).toBeTruthy()
     expect(frame.hasAttribute('data-details-collapsed')).toBe(true)
@@ -250,7 +254,7 @@ describe('AppFrame', () => {
   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(tracks(frame)).toEqual([SIDEBAR_COLLAPSED, 0])
     expect(getByTestId('sidebar-content')).toBeTruthy()
     expect(frame.hasAttribute('data-sidebar-collapsed')).toBe(true)
     const lastSidebarCall = slotCalls.filter(c => c.key === 'sidebar').at(-1)!
@@ -258,7 +262,8 @@ describe('AppFrame', () => {
   })
 
   it('viewport shrink triggers the concession chain via ResizeObserver', () => {
-    const { frame } = mountFrame()
+    const { frame, instance } = mountFrame()
+    act(() => { instance.actions.openDetails() })
     frameWidth = 1250
     act(() => { fireResize?.(); vi.advanceTimersByTime(20) })
     expect(tracks(frame)).toEqual([280, 330])
@@ -269,6 +274,8 @@ describe('AppFrame', () => {
 
   it('drag handles disappear for collapsed columns', () => {
     const { frame, instance } = mountFrame()
+    expect(frame.querySelectorAll('[class*="handle"]')).toHaveLength(1)
+    act(() => { instance.actions.openDetails() })
     expect(frame.querySelectorAll('[class*="handle"]')).toHaveLength(2)
     act(() => { instance.actions.closeDetails() })
     expect(frame.querySelectorAll('[class*="handle"]')).toHaveLength(1)
@@ -323,7 +330,7 @@ describe('AppFrame — guard branches', () => {
     frameWidth = 0
     act(() => { fireResize?.(); vi.advanceTimersByTime(20) })
     // Track template still reflects the last non-zero viewport.
-    expect(tracks(frame)).toEqual([280, 360])
+    expect(tracks(frame)).toEqual([280, 0])
   })
 })
 
@@ -338,7 +345,8 @@ describe('AppFrame — unmount with an in-flight resize frame', () => {
   })
 
   it('double resize inside one frame rides the pending rAF (??= guard)', () => {
-    const { frame } = mountFrame()
+    const { frame, instance } = mountFrame()
+    act(() => { instance.actions.openDetails() })
     frameWidth = 1250
     act(() => { fireResize?.(); fireResize?.(); vi.advanceTimersByTime(20) })
     expect(tracks(frame)).toEqual([280, 330])

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

@@ -17,9 +17,9 @@ const PERSIST_KEY = 'dsh.layout.panels'
 beforeEach(() => { localStorage.clear() })
 
 describe('createLayoutStore', () => {
-  it('initializes both panels at their default widths', () => {
+  it('initializes the sidebar at its default width and details closed', () => {
     const { store } = createLayoutStore().create()
-    expect(store.getSnapshot()).toEqual({ sidebar: SIDEBAR_DEFAULT, details: DETAILS_DEFAULT })
+    expect(store.getSnapshot()).toEqual({ sidebar: SIDEBAR_DEFAULT, details: 0 })
   })
 
   it('each create() is an independent instance (factory is not a singleton)', () => {
@@ -50,9 +50,8 @@ describe('createLayoutStore', () => {
     expect(store.getSnapshot().sidebar).toBe(SIDEBAR_DEFAULT)
   })
 
-  it('openDetails is a no-op when already open; closeDetails zeroes', () => {
+  it('openDetails uses the contract default, preserves an open width, and closeDetails zeroes', () => {
     const { store, actions } = createLayoutStore().create()
-    actions.closeDetails()
     actions.openDetails()
     expect(store.getSnapshot().details).toBe(DETAILS_DEFAULT)
     actions.setDetails(500)
@@ -65,13 +64,14 @@ describe('createLayoutStore', () => {
   it('does not persist panel geometry', () => {
     const first = createLayoutStore().create()
     first.actions.setSidebar(400)
-    first.actions.closeDetails()
+    first.actions.openDetails()
+    first.actions.setDetails(500)
     expect(localStorage.getItem(PERSIST_KEY)).toBeNull()
 
     const second = createLayoutStore().create()
     expect(second.store.getSnapshot()).toEqual({
       sidebar: SIDEBAR_DEFAULT,
-      details: DETAILS_DEFAULT,
+      details: 0,
     })
   })
 })