Merge branch 'worktree/web-carrier-chain' into worktree/web-ask-user-question

Restack the ask-user domain layer onto the carrier-chain architecture
branch. Conflict policy: runtime and ui-conversation take the
carrier-chain side (master sessions shape, dual-kind PendingCard,
'internal' envelope shell tests); the 'cancelled' wire code and its
semantics tests stay in apiproxy + ui-question (domain layer); the
smoke fixture keeps the nine-bundle success pass with the resident
question round over the carrier-chain first-describe shape.

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

@@ -1,6 +1,6 @@
 // Keyless boot-chain smoke over the REAL carrier: startWebServer + web-plugins
 // registry surface + __DSH_BOOT__ injection + built shell dist in a real
-// chromium. First describe: manifest injection + fail-loud half. Second
+// chromium. First describe: manifest injection + static serving. Second
 // describe: the settled success pass — all nine REAL tsdown bundles load
 // through the DI chain in ?fixture mode, the three-column frame appears in
 // one flip, and the resident question completes through the real UI stack.
@@ -80,15 +80,6 @@ describe('web boot chain (keyless, real carrier)', () => {
     expect(await res.text()).toContain('window.DSHClientProxy.loadPlugin')
   })
 
-  it('boots to the loading page and fail-louds the absent plugin', async () => {
-    onTestFailed(() => saveFailureShot(page, 'smoke-boot-fail-loud'))
-    await page.waitForSelector('text=HARNESS', { timeout: 10_000 })
-    await page.waitForSelector('text=Failed to load plugins', { timeout: 10_000 })
-    await page.waitForSelector('text=@probe/absent', { timeout: 2000 })
-    // The real UI must not have flipped in: the gate opens only on settled().
-    expect(await page.locator('[class*="frame"]').count()).toBe(0)
-  })
-
   it('applies the token sheets before any plugin CSS', async () => {
     const family = await page.evaluate(() => getComputedStyle(document.body).getPropertyValue('--dsw-font-family'))
     expect(family.trim().length).toBeGreaterThan(0)
@@ -145,6 +136,66 @@ describe('web boot chain success pass (keyless, nine real bundles, ?fixture)', (
     const owners = await page.evaluate(() =>
       [...document.querySelectorAll('style[data-plugin]')].map(s => (s as HTMLElement).dataset['plugin']))
     expect(owners).toContain('@deepseek-ai/dsh-client-ui-layout')
+    expect(owners).toContain('@deepseek-ai/dsh-client-ui-sidebar')
+  })
+
+  it('collapsed sidebar animates to a 56px rail with the four controls', async () => {
+    onTestFailed(() => saveFailureShot(page, 'smoke-boot-collapsed-rail'))
+    const frame = page.locator('[class*="frame"]')
+    const firstTrack = async (): Promise<string> => (await frame.evaluate(
+      el => getComputedStyle(el).gridTemplateColumns)).split(' ')[0]!
+    // The tracks transition on the deepsuite curve; assert the animated
+    // settle rather than an instant jump.
+    const settledTrack = async (px: string): Promise<void> => {
+      await expect.poll(firstTrack, { timeout: 2000 }).toBe(px)
+    }
+    await page.getByRole('button', { name: 'Collapse sidebar' }).click()
+    // Mid-collapse the wide chrome is still mounted, fading — not swapped out.
+    expect(await page.locator('text=HARNESS').count()).toBe(1)
+    await settledTrack('56px')
+    await expect.poll(() => page.locator('text=HARNESS').count(), { timeout: 2000 }).toBe(0)
+    for (const name of ['Expand sidebar', 'New session', 'New workspace', 'Search sessions', 'Settings']) {
+      await expect(page.getByRole('button', { name }).isVisible(), name).resolves.toBe(true)
+    }
+    await page.getByRole('button', { name: 'Expand sidebar' }).click()
+    await settledTrack('300px')
+    await expect(page.getByRole('button', { name: 'Collapse sidebar' }).isVisible()).resolves.toBe(true)
+    // Rail search: collapse again, the search control expands and lands in the box.
+    await page.getByRole('button', { name: 'Collapse sidebar' }).click()
+    await settledTrack('56px')
+    await page.getByRole('button', { name: 'Search sessions' }).click()
+    await settledTrack('300px')
+    const focused = await page.evaluate(() =>
+      (document.activeElement as HTMLInputElement | null)?.placeholder ?? '')
+    expect(focused).toContain('Search')
+  })
+
+  it('renders file tool rows and expands fixture reasoning from either click target', async () => {
+    onTestFailed(() => saveFailureShot(page, 'smoke-think-disclosure'))
+    await page.locator('[role="treeitem"]').first().click()
+    await page.locator('[role="treeitem"][aria-selected]').first().click()
+
+    const thinkRoot = page.locator('[data-variant="think"]').first()
+    const think = thinkRoot.getByRole('button')
+    await think.waitFor({ state: 'visible', timeout: 10_000 })
+    expect(await think.getAttribute('aria-expanded')).toBe('false')
+
+    await thinkRoot.getByText(/^思考过程 .*reasoning 内容。$/).click()
+    expect(await think.getAttribute('aria-expanded')).toBe('true')
+    expect(await thinkRoot.locator(':scope > div').count()).toBe(2)
+
+    await think.getByText('Think', { exact: true }).click()
+    expect(await think.getAttribute('aria-expanded')).toBe('false')
+
+    const editRoot = page.locator('[data-variant="edit"]').first()
+    await editRoot.waitFor({ state: 'visible', timeout: 10_000 })
+    expect(await editRoot.getByText('Edit', { exact: true }).count()).toBe(1)
+    expect(await editRoot.getByText('notes/demo.txt', { exact: true }).count()).toBe(1)
+
+    const writeRoot = page.locator('[data-variant="write"]').first()
+    await writeRoot.waitFor({ state: 'visible', timeout: 10_000 })
+    expect(await writeRoot.getByText('Write', { exact: true }).count()).toBe(1)
+    expect(await writeRoot.getByText('notes/new-demo.txt', { exact: true }).count()).toBe(1)
   })
 
   it('renders and completes the resident question through the composer slot', async () => {