Merge origin/master into worktree/sidebar-scrollbar-reveal

#1381 landed the bar's horizontal position; this branch decides when it is
drawn. The e2e keeps both scenarios and the golden carries both palettes'
pointer-state readings alongside the new edge-offset lines.

apps/web/tests/built-boot.snapshot.ts

@@ -1,7 +1,7 @@
 // @vitest-environment jsdom
 // The built-bundle boot smoke: the ONE assembled-jsdom test that loads the
 // real `packages/client/*/lib/client.js` artifacts through AppWebEntry's
-// ModuleLoader path (fetchBundle/executeBundle) and proves the boot graph
+// ModuleLoader path (loadBundle) and proves the boot graph
 // assembles — staged activation across the immediately tier and the inject
 // layers, per-plugin CSS injection, and a rendered journey reaching chat
 // content from the keyless FixtureApiClient transport.
@@ -91,11 +91,11 @@ it('boots the built plugin graph and renders a fixture session end to end', asyn
   win.__DSH_BOOT__ = { rev: 'fx', entries: PLUGINS.map(({ dir: _dir, ...plugin }) => plugin) }
   act(() => {
     const entry = new AppWebEntry(root, {
-      fetchBundle: (url) => {
+      loadBundle: async (url) => {
         const code = bundles.get(url)
-        return code === undefined ? Promise.reject(new Error(`missing built bundle ${url}`)) : Promise.resolve(code)
+        if (code === undefined) throw new Error(`missing built bundle ${url}`)
+        ;(0, eval)(code)
       },
-      executeBundle: (code) => { (0, eval)(code) },
     })
     void entry.run()
     unmount = () => { entry.dispose() }

apps/web/tests/lifecycle-chrome.e2e.ts

@@ -33,6 +33,7 @@ const RELOADED_EXPECTED = join(SNAPSHOT_DIR, 'reloaded.expected.md')
 const MODE = webSnapshotMode()
 
 const PROMPT = 'Reply with the single word LIGHTHOUSE and stop.'
+const REPLAY_PACE_MS = 100
 
 describe('web e2e: lifecycle & chrome (workspace flow / reload / dark mode)', () => {
   let scaffold: WebScaffold
@@ -42,7 +43,7 @@ describe('web e2e: lifecycle & chrome (workspace flow / reload / dark mode)', ()
   const sessionEvents: SessionEvent[] = []
 
   beforeAll(async () => {
-    scaffold = await launchWebScaffold(MODE === 'record' ? {} : { replayFixture: FIXTURE, paceMs: 15 })
+    scaffold = await launchWebScaffold(MODE === 'record' ? {} : { replayFixture: FIXTURE, paceMs: REPLAY_PACE_MS })
     scaffold.ctx.on('session/event', (_session, event: SessionEvent) => { sessionEvents.push(event) })
     browser = await chromium.launch()
     page = await newEnglishPage(browser)

apps/web/tests/search-card.snapshot.ts

@@ -128,11 +128,11 @@ describe('assembled search card', () => {
     win.__DSH_BOOT__ = { rev: 'fx', entries: PLUGINS.map(({ dir: _dir, ...plugin }) => plugin) }
     act(() => {
       const entry = new AppWebEntry(root, {
-        fetchBundle: (url) => {
+        loadBundle: async (url) => {
           const code = bundles.get(url)
-          return code === undefined ? Promise.reject(new Error(`missing built bundle ${url}`)) : Promise.resolve(code)
+          if (code === undefined) throw new Error(`missing built bundle ${url}`)
+          ;(0, eval)(code)
         },
-        executeBundle: (code) => { (0, eval)(code) },
       })
       void entry.run()
       unmount = () => { entry.dispose() }

apps/web/tests/sidebar-scrollbar.e2e.ts

@@ -112,6 +112,10 @@ interface ListMetrics {
   overflows: boolean
   /** Border-box width minus client width: the space the scrollbar takes out of the content area. */
   band: number
+  /** Distance from the scrollbar's right edge to the sidebar edge. */
+  scrollbarEdgeOffset: number
+  /** Distance from the first row background's right edge to the sidebar edge. */
+  rowEdgeInset: number
   /** Client-area right edge in viewport coordinates (`clientWidth` excludes the scrollbar band). */
   clientRight: number
   /** Border-box right edge in viewport coordinates. */
@@ -139,6 +143,8 @@ function measureList(page: Page): Promise<ListMetrics> {
     if (list === null) throw new Error('sidebar session list not in the DOM')
     const time = list.querySelector<HTMLElement>('[class*="time"]')
     if (time === null) throw new Error('no row relative-time element in the sidebar list')
+    const row = list.querySelector<HTMLElement>('[role="treeitem"]')
+    if (row === null) throw new Error('no row in the sidebar list')
     // Each indirection variable is resolved through its own throwaway probe
     // appended to the list: `var()` substitution then happens where the list
     // sits in the cascade, which is the claim, and `color` normalizes whatever
@@ -173,6 +179,9 @@ function measureList(page: Page): Promise<ListMetrics> {
     const style = getComputedStyle(list)
     const pseudoWidth = getComputedStyle(list, '::-webkit-scrollbar').width
     const barWidth = pseudoWidth === 'auto' ? 15 : Number.parseFloat(pseudoWidth)
+    const listRect = list.getBoundingClientRect()
+    const sidebarEdge = list.parentElement?.getBoundingClientRect().right
+    if (sidebarEdge === undefined) throw new Error('sidebar session list has no layout parent')
     return {
       gutter: style.scrollbarGutter,
       width: pseudoWidth,
@@ -183,9 +192,11 @@ function measureList(page: Page): Promise<ListMetrics> {
       token: resolve('--dsh-scrollbar-thumb'),
       hoverToken: resolve('--dsh-scrollbar-thumb-hover'),
       overflows: list.scrollHeight > list.clientHeight,
-      band: list.getBoundingClientRect().width - list.clientWidth,
-      clientRight: list.getBoundingClientRect().left + list.clientWidth,
-      borderRight: list.getBoundingClientRect().right,
+      band: listRect.width - list.clientWidth,
+      scrollbarEdgeOffset: sidebarEdge - listRect.right,
+      rowEdgeInset: sidebarEdge - row.getBoundingClientRect().right,
+      clientRight: listRect.left + list.clientWidth,
+      borderRight: listRect.right,
       timeRight: time.getBoundingClientRect().right,
       // The bar is drawn in the rightmost `barWidth` of the border box, whether
       // or not that space was reserved. Its width comes from the sheet where the
@@ -194,7 +205,28 @@ function measureList(page: Page): Promise<ListMetrics> {
       // absent. Taking the UA width as the fallback is what keeps the assertion
       // honest: assuming 0 there would report no occlusion precisely in the
       // state that has it.
-      timeCoveredBy: Math.max(0, time.getBoundingClientRect().right - (list.getBoundingClientRect().right - barWidth)),
+      timeCoveredBy: Math.max(0, time.getBoundingClientRect().right - (listRect.right - barWidth)),
+    }
+  })
+}
+
+/**
+ * Measure only overflow and row inset, which remain observable when every
+ * session is hidden under a collapsed workspace group.
+ * @param page - the page under test.
+ * @returns the list overflow state and first row's trailing inset.
+ */
+function measureRowInset(page: Page): Promise<Pick<ListMetrics, 'overflows' | 'rowEdgeInset'>> {
+  return page.evaluate(() => {
+    const list = document.querySelector<HTMLElement>('[role="tree"][aria-label="Sessions"]')
+    if (list === null) throw new Error('sidebar session list not in the DOM')
+    const row = list.querySelector<HTMLElement>('[role="treeitem"]')
+    if (row === null) throw new Error('no row in the sidebar list')
+    const sidebarEdge = list.parentElement?.getBoundingClientRect().right
+    if (sidebarEdge === undefined) throw new Error('sidebar session list has no layout parent')
+    return {
+      overflows: list.scrollHeight > list.clientHeight,
+      rowEdgeInset: sidebarEdge - row.getBoundingClientRect().right,
     }
   })
 }
@@ -257,6 +289,8 @@ function renderGeometry(light: PaletteMetrics, dark: PaletteMetrics): string {
     `- --dsh-scrollbar-thumb-hover, pointer over the list: ${metrics.hoverToken}`,
     `- list overflows: ${String(metrics.overflows)}`,
     `- reserved band: ${String(metrics.band)}px`,
+    `- scrollbar inset from the sidebar edge: ${String(metrics.scrollbarEdgeOffset)}px`,
+    `- row background inset from the sidebar edge: ${String(metrics.rowEdgeInset)}px`,
     `- relative time covered by the bar: ${String(metrics.timeCoveredBy)}px`,
     `- relative time ends inside the content area: ${String(metrics.timeRight <= metrics.clientRight)}`,
     `- content area ends before the border box: ${String(metrics.clientRight < metrics.borderRight)}`,
@@ -380,6 +414,8 @@ describe('web e2e: sidebar session list scrollbar (reserved gutter / themed thum
     // drawn over it. Removing the declaration makes it exactly 0. The value
     // itself is not pinned — it tracks `scrollbar-width` and the platform.
     expect(metrics.band).toBeGreaterThan(0)
+    expect(metrics.scrollbarEdgeOffset).toBe(2)
+    expect(metrics.rowEdgeInset).toBe(12)
     // The reported symptom, stated directly: no part of the row's relative time
     // lies under the bar. Measures 7 on clean master — the `h` of `1h` is the
     // covered part. Unlike the client-edge comparison below it does not go
@@ -426,6 +462,20 @@ describe('web e2e: sidebar session list scrollbar (reserved gutter / themed thum
     expect(tripwire.pageErrors).toEqual([])
   }, 60_000)
 
+  it('keeps the row background inset when overflow disappears', async () => {
+    onTestFailed(() => saveFailureShot(page, 'web-e2e-sidebar-scrollbar-stable-inset'))
+    expect(await measureRowInset(page)).toEqual({ overflows: true, rowEdgeInset: 12 })
+    const bucket = page.getByText('Ungrouped', { exact: true }).locator('..').locator('..')
+    await bucket.click()
+    try {
+      await expect.poll(async () => (await measureRowInset(page)).overflows, { timeout: 10_000 }).toBe(false)
+      expect(await measureRowInset(page)).toEqual({ overflows: false, rowEdgeInset: 12 })
+    } finally {
+      await expandSeededSessions(page)
+    }
+    expect(tripwire.pageErrors).toEqual([])
+  }, 60_000)
+
   it('renders the themed thumb through the WebKit path in both palettes', async () => {
     onTestFailed(() => saveFailureShot(page, 'web-e2e-sidebar-scrollbar-theme'))
     const light = await measureList(page)

apps/web/tests/snapshots/sidebar-scrollbar/geometry.expected.md

@@ -13,6 +13,8 @@
 - --dsh-scrollbar-thumb-hover, pointer over the list: rgb(212, 212, 212)
 - list overflows: true
 - reserved band: 8px
+- scrollbar inset from the sidebar edge: 2px
+- row background inset from the sidebar edge: 12px
 - relative time covered by the bar: 0px
 - relative time ends inside the content area: true
 - content area ends before the border box: true
@@ -30,6 +32,8 @@
 - --dsh-scrollbar-thumb-hover, pointer over the list: rgb(84, 85, 87)
 - list overflows: true
 - reserved band: 8px
+- scrollbar inset from the sidebar edge: 2px
+- row background inset from the sidebar edge: 12px
 - relative time covered by the bar: 0px
 - relative time ends inside the content area: true
 - content area ends before the border box: true