test(web): close the per-file coverage gate for the session-list surfaces

New and touched sources reach the CI per-file 100% thresholds: HoverCard
(timers, placement clamp, disabled guard), Menu label/danger/pointer-leave
branches, WorkspaceBrowser (mode switch, search, rail icons, rename dialog,
drag), rows and tree derivations, the workspace fixture stubs, the rename/
insertSessionBefore wire rows, and the entity move semantics. HoverCard's
position state narrows to {left, top} (equivalent refactor, no behavior
change).

packages/client/ui-workspace/src/client/WorkspaceBrowser.tsx

@@ -48,6 +48,7 @@ function GroupByMenu({ groupBy, onPick }: {
       items={GROUP_BY_ITEMS}
       selectedId={groupBy}
       onSelect={(id) => {
+        /* v8 ignore next -- narrowing guard: the heading label is not selectable, so the only arriving ids are the two modes. */
         if (id === 'workspace' || id === 'flat') onPick(id)
         setOpen(false)
       }}
@@ -137,6 +138,7 @@ function SessionTree({ useSessions, startSession, open, workspaces, query, onRen
               onRename={group.workspaceId === undefined
                 ? undefined
                 : () => {
+                    /* v8 ignore next -- narrowing guard: the closure is only created for real-workspace groups. */
                     if (group.workspaceId !== undefined) onRenameRequest(group.workspaceId, group.label)
                   }}
             />
@@ -154,9 +156,11 @@ function SessionTree({ useSessions, startSession, open, workspaces, query, onRen
                 active: sameGroupDrag,
                 marker: sameGroupDrag && drag.over?.id === node.id ? drag.over.half : null,
                 hover: (half: 'before' | 'after') => {
+                  /* v8 ignore next -- narrowing guard: Rows gates hover on `active`, which is false while the drag state is null. */
                   setDrag(d => (d === null ? d : { ...d, over: { id: node.id, half } }))
                 },
                 drop: (half: 'before' | 'after') => {
+                  /* v8 ignore next -- narrowing guard: Rows gates drop on `active`, which is false while the drag state is null. */
                   if (drag === null) return
                   const roots = group.sessions
                   // Anchor = the row the insert line points at ('after' means
@@ -218,6 +222,7 @@ function FlatList({ useSessions, open, query }: Pick<SessionTreeProps, 'useSessi
             currentId={list.current}
             now={now}
             onOpen={open}
+            /* v8 ignore next -- required-prop filler: flat rows render no twist, so it never fires. */
             onToggle={() => {}}
             flat
           />

packages/client/ui-workspace/tests/rows.spec.tsx

@@ -1,7 +1,8 @@
 // @vitest-environment jsdom
 import { afterEach, describe, expect, it, vi } from 'vitest'
-import { cleanup, fireEvent, render, screen } from '@testing-library/react'
+import { act, cleanup, createEvent, fireEvent, render, screen } from '@testing-library/react'
 import type { SessionId, WorkspaceId } from '@deepseek-ai/dsh-client-runtime/client'
+import type { RowDragProps } from '../src/client/rows/Rows.tsx'
 import { IntentRowItem, ProjectRowItem, SessionNodeItem } from '../src/client/rows/Rows.tsx'
 import type { GroupNode, SessionNode } from '../src/client/tree.ts'
 
@@ -10,6 +11,32 @@ afterEach(cleanup)
 const sid = (id: string) => id as SessionId
 const wid = (id: string) => id as WorkspaceId
 
+/** Half detection reads the row rect; jsdom rects are all-zero by default. */
+function stubRect(row: HTMLElement): void {
+  row.getBoundingClientRect = () => ({
+    top: 100, bottom: 134, left: 0, right: 200, width: 200, height: 34,
+    x: 0, y: 100, toJSON: () => ({}),
+  } as DOMRect)
+}
+
+function dragProps(overrides: Partial<RowDragProps> = {}): RowDragProps {
+  return {
+    start: vi.fn(), active: false, marker: null,
+    hover: vi.fn(), drop: vi.fn(), end: vi.fn(),
+    ...overrides,
+  }
+}
+
+const dataTransfer = { effectAllowed: '', dropEffect: '' }
+
+/** jsdom lacks DragEvent — the fireEvent fallback drops clientY, so pin it on the built event. */
+function fireDrag(row: HTMLElement, kind: 'dragOver' | 'drop', clientY: number): void {
+  const event = kind === 'dragOver' ? createEvent.dragOver(row) : createEvent.drop(row)
+  Object.defineProperty(event, 'clientY', { value: clientY })
+  Object.defineProperty(event, 'dataTransfer', { value: { ...dataTransfer } })
+  fireEvent(row, event)
+}
+
 describe('workspace browser rows', () => {
   it('renders an active Workspace and keeps its create action separate from toggling', () => {
     const onToggle = vi.fn()
@@ -73,4 +100,152 @@ describe('workspace browser rows', () => {
     expect(screen.getByRole('treeitem').getAttribute('aria-selected')).toBe('false')
     expect(screen.getByRole('treeitem').style.paddingLeft).toBe('24px')
   })
+
+  it('workspace row menu opens on the ellipsis, renames, and shows the danger delete row', () => {
+    const onRename = vi.fn()
+    const onToggle = vi.fn()
+    const group: GroupNode = {
+      key: 'project', workspaceId: wid('project'), cwd: '/projects/project', label: 'Project',
+      sessionCount: 0, expanded: false, containsCurrent: false, intentHere: false, sessions: [],
+    }
+    render(<ProjectRowItem group={group} onToggle={onToggle} onCreate={vi.fn()} onRename={onRename} />)
+    fireEvent.click(screen.getByRole('button', { name: 'Workspace actions for Project' }))
+    // Opening the menu neither toggles the group nor renames yet.
+    expect(onToggle).not.toHaveBeenCalled()
+    expect(screen.getByRole('menuitem', { name: 'Delete workspace' }).className).toMatch(/danger/)
+    fireEvent.click(screen.getByRole('menuitem', { name: 'Rename' }))
+    expect(onRename).toHaveBeenCalledOnce()
+    expect(screen.queryByRole('menu')).toBeNull()
+    // Delete stays visual-only: selecting it just closes the menu.
+    fireEvent.click(screen.getByRole('button', { name: 'Workspace actions for Project' }))
+    fireEvent.click(screen.getByRole('menuitem', { name: 'Delete workspace' }))
+    expect(screen.queryByRole('menu')).toBeNull()
+    expect(onRename).toHaveBeenCalledOnce()
+    // Escape closes without selecting (Menu onClose path).
+    fireEvent.click(screen.getByRole('button', { name: 'Workspace actions for Project' }))
+    fireEvent.keyDown(document, { key: 'Escape' })
+    expect(screen.queryByRole('menu')).toBeNull()
+  })
+
+  it('ungrouped bucket renders no workspace menu', () => {
+    const group: GroupNode = {
+      key: '', workspaceId: undefined, cwd: undefined, label: 'Ungrouped',
+      sessionCount: 0, expanded: false, containsCurrent: false, intentHere: false, sessions: [],
+    }
+    render(<ProjectRowItem group={group} onToggle={vi.fn()} onCreate={vi.fn()} />)
+    expect(screen.queryByRole('button', { name: /Workspace actions/ })).toBeNull()
+  })
+
+  it('session row menu opens without opening the session and closes on selection', () => {
+    const onOpen = vi.fn()
+    const node: SessionNode = {
+      id: sid('s1'), title: 'One', children: [], hasChildren: false,
+      expanded: false, running: false, updatedAt: 0,
+    }
+    render(<SessionNodeItem node={node} depth={0} currentId={undefined} now={0} onOpen={onOpen} onToggle={vi.fn()} />)
+    fireEvent.click(screen.getByRole('button', { name: 'Session actions for One' }))
+    expect(onOpen).not.toHaveBeenCalled()
+    expect(screen.getByRole('menuitem', { name: 'Delete session' }).className).toMatch(/danger/)
+    fireEvent.click(screen.getByRole('menuitem', { name: 'Fork session' }))
+    expect(screen.queryByRole('menu')).toBeNull()
+    expect(onOpen).not.toHaveBeenCalled()
+    // Escape closes without selecting (Menu onClose path).
+    fireEvent.click(screen.getByRole('button', { name: 'Session actions for One' }))
+    fireEvent.keyDown(document, { key: 'Escape' })
+    expect(screen.queryByRole('menu')).toBeNull()
+  })
+
+  it('flat variant renders no twist even for a parent and ignores toggling', () => {
+    const node: SessionNode = {
+      id: sid('p'), title: 'Parent', children: [], hasChildren: true,
+      expanded: false, running: false, updatedAt: 0,
+    }
+    render(<SessionNodeItem node={node} depth={0} currentId={undefined} now={0} onOpen={vi.fn()} onToggle={vi.fn()} flat />)
+    expect(screen.queryByRole('button', { name: 'Expand' })).toBeNull()
+  })
+
+  it('shows the hover card after the dwell and suppresses it while the row menu is open', () => {
+    vi.useFakeTimers()
+    try {
+      const node: SessionNode = {
+        id: sid('s1'), title: 'Hovered', children: [], hasChildren: false,
+        expanded: false, running: true, updatedAt: 0,
+      }
+      render(<SessionNodeItem node={node} depth={0} currentId={undefined} now={60_000} onOpen={vi.fn()} onToggle={vi.fn()} />)
+      const wrapper = screen.getByRole('treeitem').parentElement as HTMLElement
+      fireEvent.pointerEnter(wrapper)
+      act(() => { vi.advanceTimersByTime(500) })
+      // Card body: full title + relative time + running status.
+      expect(screen.getAllByText('Hovered')).toHaveLength(2)
+      expect(screen.getByText('1min ago')).toBeTruthy()
+      expect(screen.getByText('Running')).toBeTruthy()
+      fireEvent.pointerLeave(wrapper)
+      // Menu open (disabled=true) suppresses the card for the same hover.
+      fireEvent.click(screen.getByRole('button', { name: 'Session actions for Hovered' }))
+      fireEvent.pointerEnter(wrapper)
+      act(() => { vi.advanceTimersByTime(1000) })
+      expect(screen.queryByText('1min ago')).toBeNull()
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('idle hover card shows the Idle status line', () => {
+    vi.useFakeTimers()
+    try {
+      const node: SessionNode = {
+        id: sid('s1'), title: 'Quiet', children: [], hasChildren: false,
+        expanded: false, running: false, updatedAt: 0,
+      }
+      render(<SessionNodeItem node={node} depth={0} currentId={undefined} now={0} onOpen={vi.fn()} onToggle={vi.fn()} />)
+      fireEvent.pointerEnter(screen.getByRole('treeitem').parentElement as HTMLElement)
+      act(() => { vi.advanceTimersByTime(500) })
+      expect(screen.getByText('Idle')).toBeTruthy()
+      expect(screen.getByText('now ago')).toBeTruthy()
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('draggable row wires start/end and gates hover/drop on an active same-group drag', () => {
+    const node: SessionNode = {
+      id: sid('s1'), title: 'Drag me', children: [], hasChildren: false,
+      expanded: false, running: false, updatedAt: 0,
+    }
+    const inactive = dragProps()
+    const { rerender } = render(
+      <SessionNodeItem node={node} depth={0} currentId={undefined} now={0} onOpen={vi.fn()} onToggle={vi.fn()} drag={inactive} />,
+    )
+    const row = screen.getByRole('treeitem')
+    stubRect(row)
+    expect(row.getAttribute('draggable')).toBe('true')
+    fireEvent.dragStart(row, { dataTransfer })
+    expect(inactive.start).toHaveBeenCalledOnce()
+    // Inactive drag: hover and drop are rejected.
+    fireEvent.dragOver(row, { dataTransfer })
+    fireEvent.drop(row, { dataTransfer })
+    expect(inactive.hover).not.toHaveBeenCalled()
+    expect(inactive.drop).not.toHaveBeenCalled()
+    fireEvent.dragEnd(row)
+    expect(inactive.end).toHaveBeenCalledOnce()
+
+    const active = dragProps({ active: true, marker: 'before' })
+    rerender(
+      <SessionNodeItem node={node} depth={0} currentId={undefined} now={0} onOpen={vi.fn()} onToggle={vi.fn()} drag={active} />,
+    )
+    stubRect(screen.getByRole('treeitem'))
+    // Top half hovers/drops 'before'; bottom half 'after' (row mid = 117).
+    fireDrag(screen.getByRole('treeitem'), 'dragOver', 105)
+    expect(active.hover).toHaveBeenCalledWith('before')
+    fireDrag(screen.getByRole('treeitem'), 'dragOver', 130)
+    expect(active.hover).toHaveBeenCalledWith('after')
+    fireDrag(screen.getByRole('treeitem'), 'drop', 130)
+    expect(active.drop).toHaveBeenCalledWith('after')
+
+    const after = dragProps({ active: true, marker: 'after' })
+    rerender(
+      <SessionNodeItem node={node} depth={0} currentId={undefined} now={0} onOpen={vi.fn()} onToggle={vi.fn()} drag={after} />,
+    )
+    expect(screen.getByRole('treeitem').className).toMatch(/dropAfter/)
+  })
 })

packages/client/ui-workspace/tests/tree.spec.ts

@@ -2,7 +2,8 @@ import { describe, expect, it } from 'vitest'
 import type {
   SessionId, SessionListState, SessionSummary, WorkspaceId, WorkspaceView,
 } from '@deepseek-ai/dsh-client-runtime/client'
-import { deriveGroups, formatRelativeTime, projectLabel, UNGROUPED_KEY, UNGROUPED_LABEL } from '../src/client/tree.ts'
+import { deriveFlat, deriveGroups, formatRelativeTime, projectLabel, UNGROUPED_KEY, UNGROUPED_LABEL } from '../src/client/tree.ts'
+import { createWorkspaceViewStore } from '../src/client/stores.ts'
 
 const sid = (id: string) => id as SessionId
 const wid = (id: string) => id as WorkspaceId
@@ -52,6 +53,12 @@ describe('deriveGroups', () => {
     expect(deriveGroups({ ...list(), intent: hiddenIntent }, [target], view())[0]!.intentHere).toBe(false)
   })
 
+  it('an Intent no longer forces its target group expanded (viewer owns expansion)', () => {
+    const intent = { sessionId: sid('intent'), target: { kind: 'workspace' as const, workspaceId: wid('first') }, prompt: '', phase: 'connecting' as const }
+    const groups = deriveGroups({ ...list(), intent }, [workspace('first', [])], view())
+    expect(groups[0]).toEqual(expect.objectContaining({ intentHere: true, expanded: false }))
+  })
+
   it('search filters real Sessions and omits the Intent placeholder', () => {
     const intent = { sessionId: sid('intent'), target: { kind: 'workspace' as const, workspaceId: wid('first') }, prompt: '', phase: 'ready' as const }
     const groups = deriveGroups({ ...list(summary('match', 1)), intent }, [workspace('first', ['match'])], view([], 'match'))
@@ -135,6 +142,39 @@ describe('deriveGroups', () => {
   })
 })
 
+describe('deriveFlat', () => {
+  it('flattens every session — fork children included — newest-first with id tiebreak', () => {
+    const parent = summary('parent', 10)
+    const child = { ...summary('child', 30), parentId: parent.id }
+    const tieB = summary('tie-b', 20)
+    const tieA = summary('tie-a', 20)
+    const rows = deriveFlat(list(parent, child, tieB, tieA), { query: '' })
+    expect(rows.map(row => row.id)).toEqual([sid('child'), sid('tie-a'), sid('tie-b'), sid('parent')])
+    // Rows are branch-free: no children, no expansion.
+    expect(rows.every(row => row.children.length === 0 && !row.hasChildren && !row.expanded)).toBe(true)
+  })
+
+  it('search filters by case-insensitive display-title substring', () => {
+    const hit = { ...summary('hit', 2), displayTitle: 'Needle row' }
+    const miss = { ...summary('miss', 1), displayTitle: 'Other' }
+    expect(deriveFlat(list(hit, miss), { query: ' NEEDLE ' }).map(row => row.id)).toEqual([sid('hit')])
+  })
+
+  it('tolerates ids whose summary has not landed yet', () => {
+    const partial: SessionListState = { ...list(summary('present', 1)), ids: [sid('ghost'), sid('present')] }
+    expect(deriveFlat(partial, { query: '' }).map(row => row.id)).toEqual([sid('present')])
+  })
+})
+
+describe('createWorkspaceViewStore', () => {
+  it('defaults to workspace grouping; setGroupBy is the sole mutation', () => {
+    const store = createWorkspaceViewStore().create()
+    expect(store.getSnapshot().groupBy).toBe('workspace')
+    store.actions.setGroupBy('flat')
+    expect(store.getSnapshot().groupBy).toBe('flat')
+  })
+})
+
 describe('projectLabel', () => {
   it('uses the Ungrouped fallback and extracts POSIX and Windows basenames', () => {
     expect(projectLabel(undefined)).toBe(UNGROUPED_LABEL)

packages/client/ui-workspace/tests/workspace-browser.spec.tsx

@@ -0,0 +1,458 @@
+// @vitest-environment jsdom
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { act, cleanup, createEvent, fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { bindSnapshotSelector } from '@deepseek-ai/dsh-client-web-react'
+import type {
+  SessionId, SessionListState, SessionSummary, WorkspaceId, WorkspaceListState, WorkspaceView,
+} from '@deepseek-ai/dsh-client-runtime/client'
+import type { WorkspaceBrowserProps } from '../src/client/contract/slots.ts'
+import { createWorkspaceViewStore } from '../src/client/stores.ts'
+import { WorkspaceBrowser } from '../src/client/WorkspaceBrowser.tsx'
+
+afterEach(cleanup)
+beforeEach(() => { localStorage.clear() })
+
+const sid = (id: string) => id as SessionId
+const wid = (id: string) => id as WorkspaceId
+const summary = (id: string, updatedAt: number, overrides: Partial<SessionSummary> = {}): SessionSummary => ({
+  id: sid(id), displayTitle: id, running: false, updatedAt, ...overrides,
+})
+const sessionState = (items: readonly SessionSummary[], overrides: Partial<SessionListState> = {}): SessionListState => ({
+  ids: items.map(item => item.id),
+  byId: Object.fromEntries(items.map(item => [item.id, item])),
+  current: undefined,
+  phase: 'ready',
+  intent: undefined,
+  ...overrides,
+})
+const workspace = (id: string, sessionIds: string[], title = id): WorkspaceView => ({
+  workspaceId: wid(id), path: `/projects/${id}`, title,
+  sessionIds: sessionIds.map(sid), createdAt: '2026-01-01T00:00:00.000Z', updatedAt: '2026-01-01T00:00:00.000Z',
+})
+const workspaceState = (items: readonly WorkspaceView[]): WorkspaceListState => ({
+  items, intent: undefined, state: 'idle', phase: 'ready', error: null, baselinesReady: true,
+  recentWorkspaceId: items[0]?.workspaceId,
+})
+const hook = <T,>(snapshot: T) => <S,>(selector: (state: T) => S): S => selector(snapshot)
+
+/** jsdom lacks DragEvent — the fireEvent fallback drops clientY, so pin it on the built event. */
+function fireDrag(row: HTMLElement, kind: 'dragOver' | 'drop', clientY: number): void {
+  const event = kind === 'dragOver' ? createEvent.dragOver(row) : createEvent.drop(row)
+  Object.defineProperty(event, 'clientY', { value: clientY })
+  Object.defineProperty(event, 'dataTransfer', { value: { effectAllowed: '', dropEffect: '' } })
+  fireEvent(row, event)
+}
+
+function mount(overrides: Partial<WorkspaceBrowserProps> = {}) {
+  const store = createWorkspaceViewStore().create()
+  const props: WorkspaceBrowserProps = {
+    wide: true,
+    expandSidebar: vi.fn(),
+    useSessions: hook(sessionState([])),
+    useWorkspaces: hook(workspaceState([])),
+    useStore: bindSnapshotSelector(store),
+    actions: store.actions,
+    startSession: vi.fn(),
+    open: vi.fn(),
+    renameWorkspace: vi.fn(async () => {}),
+    insertSessionBefore: vi.fn(async () => {}),
+    createWorkspace: vi.fn(async () => workspace('created', [])),
+    ...overrides,
+  }
+  const view = render(<WorkspaceBrowser {...props} />)
+  return { view, props, store }
+}
+
+/** Re-render with (possibly) changed props — WorkspaceBrowser has no side channel. */
+function rerender(b: ReturnType<typeof mount>, overrides: Partial<WorkspaceBrowserProps>) {
+  Object.assign(b.props, overrides)
+  b.view.rerender(<WorkspaceBrowser {...b.props} />)
+}
+
+describe('WorkspaceBrowser', () => {
+  it('renders the grouped tree by default and switches to the flat list via Group by', () => {
+    const sessions = sessionState([summary('alpha-s', 2), summary('beta-s', 1)])
+    const b = mount({
+      useSessions: hook(sessions),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['alpha-s']), workspace('beta', ['beta-s'])])),
+    })
+    expect(screen.getByText('Workspaces')).toBeTruthy()
+    expect(screen.getByText('alpha')).toBeTruthy()
+    // Sessions hidden while their group is folded.
+    expect(screen.queryByText('alpha-s')).toBeNull()
+
+    fireEvent.click(screen.getByRole('button', { name: 'Group by' }))
+    expect(screen.getByText('Group by')).toBeTruthy() // the menu heading label
+    fireEvent.click(screen.getByRole('menuitem', { name: 'In one list' }))
+    // Store-driven flip: title changes, rows flatten newest-first, headers gone.
+    expect(b.store.getSnapshot().groupBy).toBe('flat')
+    expect(screen.getByText('Sessions')).toBeTruthy()
+    expect(screen.queryByText('alpha')).toBeNull()
+    expect(screen.getByText('alpha-s')).toBeTruthy()
+    expect(screen.getByText('beta-s')).toBeTruthy()
+
+    // Back to workspace grouping through the same menu.
+    fireEvent.click(screen.getByRole('button', { name: 'Group by' }))
+    fireEvent.click(screen.getByRole('menuitem', { name: 'WorkSpace' }))
+    expect(b.store.getSnapshot().groupBy).toBe('workspace')
+    expect(screen.getByText('Workspaces')).toBeTruthy()
+
+    // Escape closes the menu without picking.
+    fireEvent.click(screen.getByRole('button', { name: 'Group by' }))
+    fireEvent.keyDown(document, { key: 'Escape' })
+    expect(screen.queryByRole('menu')).toBeNull()
+    expect(b.store.getSnapshot().groupBy).toBe('workspace')
+  })
+
+  it('expands a group on click and opens a session row', () => {
+    const open = vi.fn()
+    mount({
+      useSessions: hook(sessionState([summary('alpha-s', 1)])),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['alpha-s'])])),
+      open,
+    })
+    fireEvent.click(screen.getByText('alpha'))
+    fireEvent.click(screen.getByText('alpha-s'))
+    expect(open).toHaveBeenCalledWith(sid('alpha-s'))
+    // Collapse hides the row again.
+    fireEvent.click(screen.getByText('alpha'))
+    expect(screen.queryByText('alpha-s')).toBeNull()
+  })
+
+  it('unfolds a session subtree through the row twist', () => {
+    const parent = summary('parent-s', 2)
+    const child = { ...summary('child-s', 1), parentId: parent.id }
+    mount({
+      useSessions: hook(sessionState([parent, child])),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['parent-s', 'child-s'])])),
+    })
+    fireEvent.click(screen.getByText('alpha'))
+    expect(screen.queryByText('child-s')).toBeNull()
+    fireEvent.click(screen.getByRole('button', { name: 'Expand' }))
+    expect(screen.getByText('child-s')).toBeTruthy()
+    fireEvent.click(screen.getByRole('button', { name: 'Collapse' }))
+    expect(screen.queryByText('child-s')).toBeNull()
+  })
+
+  it('auto-expands the selected session group and starts a session from the group ＋', () => {
+    const startSession = vi.fn()
+    mount({
+      useSessions: hook(sessionState([summary('alpha-s', 1)], { current: sid('alpha-s') })),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['alpha-s'])])),
+      startSession,
+    })
+    // The current-group effect expanded the owning group without a click.
+    expect(screen.getByText('alpha-s')).toBeTruthy()
+    fireEvent.click(screen.getByRole('button', { name: 'New session in alpha' }))
+    expect(startSession).toHaveBeenCalledWith(wid('alpha'))
+  })
+
+  it('auto-expands the Ungrouped bucket for a loose current session; its header has no menu and its ＋ is inert', () => {
+    const startSession = vi.fn()
+    mount({
+      useSessions: hook(sessionState([summary('loose', 1)], { current: sid('loose') })),
+      useWorkspaces: hook(workspaceState([workspace('alpha', [])])),
+      startSession,
+    })
+    // The loose session's group is UNGROUPED_KEY: expanded by the effect.
+    expect(screen.getByText('loose')).toBeTruthy()
+    expect(screen.queryByRole('button', { name: 'Workspace actions for Ungrouped' })).toBeNull()
+    fireEvent.click(screen.getByRole('button', { name: 'New session in Ungrouped' }))
+    expect(startSession).not.toHaveBeenCalled()
+  })
+
+  it('keeps an already-expanded group when the selection moves within it', () => {
+    const first = sessionState([summary('a', 2), summary('b', 1)], { current: sid('a') })
+    const b = mount({
+      useSessions: hook(first),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['a', 'b'])])),
+    })
+    expect(screen.getByText('a')).toBeTruthy()
+    // Selection hop inside the same group: the effect re-runs and leaves the
+    // expansion list unchanged (no duplicate key, group still open).
+    rerender(b, { useSessions: hook({ ...first, current: sid('b') }) })
+    expect(screen.getByText('b')).toBeTruthy()
+    fireEvent.click(screen.getByText('alpha'))
+    expect(screen.queryByText('b')).toBeNull()
+  })
+
+  it('renders the intent placeholder in both modes', () => {
+    const intent = { sessionId: sid('intent'), target: { kind: 'workspace' as const, workspaceId: wid('alpha') }, prompt: '', phase: 'connecting' as const }
+    const sessions = sessionState([], { intent, current: sid('intent') })
+    const b = mount({
+      useSessions: hook(sessions),
+      useWorkspaces: hook(workspaceState([workspace('alpha', [])])),
+    })
+    // Grouped: the current-group effect expands the target group.
+    expect(screen.getByText('New session')).toBeTruthy()
+    b.store.actions.setGroupBy('flat')
+    rerender(b, {})
+    expect(screen.getByText('New session')).toBeTruthy()
+  })
+
+  it('searches across groups, clears via the clear button, and shows the empty states', () => {
+    const sessions = sessionState([
+      summary('needle-row', 2, { displayTitle: 'Needle row' }),
+      summary('other-row', 1, { displayTitle: 'Other row' }),
+    ])
+    mount({
+      useSessions: hook(sessions),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['needle-row', 'other-row'])])),
+    })
+    const input = screen.getByPlaceholderText<HTMLInputElement>('Search name, keywords...')
+    fireEvent.change(input, { target: { value: 'needle' } })
+    // Search forces matches visible without expansion state.
+    expect(screen.getByText('Needle row')).toBeTruthy()
+    expect(screen.queryByText('Other row')).toBeNull()
+    fireEvent.change(input, { target: { value: 'zzz' } })
+    expect(screen.getByText('No matches')).toBeTruthy()
+    fireEvent.click(screen.getByRole('button', { name: 'Clear search' }))
+    expect(input.value).toBe('')
+    // Clicking the field row focuses the input (wide mode).
+    fireEvent.click(input.parentElement as HTMLElement)
+    expect(document.activeElement).toBe(input)
+  })
+
+  it('shows the no-sessions empty state in both modes', () => {
+    const b = mount()
+    expect(screen.getByText('No sessions yet')).toBeTruthy()
+    b.store.actions.setGroupBy('flat')
+    rerender(b, {})
+    expect(screen.getByText('No sessions yet')).toBeTruthy()
+    // Flat search misses show No matches.
+    fireEvent.change(screen.getByPlaceholderText('Search name, keywords...'), { target: { value: 'x' } })
+    expect(screen.getByText('No matches')).toBeTruthy()
+  })
+
+  it('rail state renders icon controls that request expansion', () => {
+    vi.useFakeTimers()
+    try {
+      const expandSidebar = vi.fn()
+      const b = mount({ wide: false, expandSidebar })
+      // No wide chrome in rail state.
+      expect(screen.queryByText('Workspaces')).toBeNull()
+      expect(screen.queryByPlaceholderText('Search name, keywords...')).toBeNull()
+      fireEvent.click(screen.getByRole('button', { name: 'Search sessions' }))
+      expect(expandSidebar).toHaveBeenCalledTimes(1)
+      // The wide flip mounts the input and focuses it after the slide.
+      rerender(b, { wide: true })
+      const input = screen.getByPlaceholderText('Search name, keywords...')
+      act(() => { vi.advanceTimersByTime(300) })
+      expect(document.activeElement).toBe(input)
+      // Wide search button is decorative (tabIndex -1, no expand call).
+      fireEvent.click(screen.getByRole('button', { name: 'Search sessions' }))
+      expect(expandSidebar).toHaveBeenCalledTimes(1)
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('rail create-workspace expands the shell and opens the picker; wide toggles in place', () => {
+    const expandSidebar = vi.fn()
+    const b = mount({ wide: false, expandSidebar, useWorkspaces: hook(workspaceState([workspace('alpha', [])])) })
+    fireEvent.click(screen.getByRole('button', { name: 'Create workspace' }))
+    expect(expandSidebar).toHaveBeenCalledTimes(1)
+    rerender(b, { wide: true })
+    // The picker menu is open (anchored on the ＋); picking starts a session.
+    fireEvent.click(screen.getByRole('menuitem', { name: 'alpha' }))
+    expect(b.props.startSession).toHaveBeenCalledWith(wid('alpha'))
+    expect(screen.queryByRole('menu')).toBeNull()
+    // Wide toggle: open and close without expand requests.
+    fireEvent.click(screen.getByRole('button', { name: 'Create workspace' }))
+    expect(screen.getByRole('menu')).toBeTruthy()
+    fireEvent.click(screen.getByRole('button', { name: 'Create workspace' }))
+    expect(screen.queryByRole('menu')).toBeNull()
+    expect(expandSidebar).toHaveBeenCalledTimes(1)
+
+    // Escape closes the picker through its own onClose.
+    fireEvent.click(screen.getByRole('button', { name: 'Create workspace' }))
+    fireEvent.keyDown(document, { key: 'Escape' })
+    expect(screen.queryByRole('menu')).toBeNull()
+  })
+
+  it('drag reorder reports the anchor to insertSessionBefore and skips no-op drops', () => {
+    const insertSessionBefore = vi.fn(async () => {})
+    const sessions = sessionState([summary('one', 3), summary('two', 2), summary('three', 1)])
+    mount({
+      useSessions: hook(sessions),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['one', 'two', 'three'])])),
+      insertSessionBefore,
+    })
+    fireEvent.click(screen.getByText('alpha'))
+    const rows = screen.getAllByRole('treeitem').slice(1) // drop the group header
+    const [one, , three] = rows as [HTMLElement, HTMLElement, HTMLElement]
+    three.getBoundingClientRect = () => ({
+      top: 200, bottom: 234, left: 0, right: 200, width: 200, height: 34, x: 0, y: 200, toJSON: () => ({}),
+    } as DOMRect)
+    const dataTransfer = { effectAllowed: '', dropEffect: '' }
+    fireEvent.dragStart(one, { dataTransfer })
+    // Drop on the top half of "three": insert one before three.
+    fireDrag(three, 'dragOver', 205)
+    fireDrag(three, 'drop', 205)
+    expect(insertSessionBefore).toHaveBeenCalledWith(wid('alpha'), sid('one'), sid('three'))
+
+    // Dropping right back onto its own position is a no-op — top half
+    // (anchor = itself) and bottom half (anchor = the next root) alike.
+    fireEvent.dragStart(one, { dataTransfer })
+    one.getBoundingClientRect = () => ({
+      top: 100, bottom: 134, left: 0, right: 200, width: 200, height: 34, x: 0, y: 100, toJSON: () => ({}),
+    } as DOMRect)
+    fireDrag(one, 'dragOver', 105)
+    fireDrag(one, 'drop', 105)
+    expect(insertSessionBefore).toHaveBeenCalledTimes(1)
+    fireEvent.dragStart(one, { dataTransfer })
+    fireDrag(one, 'drop', 130)
+    expect(insertSessionBefore).toHaveBeenCalledTimes(1)
+  })
+
+  it('still sends the reorder when the dragged row left the group mid-drag', () => {
+    const insertSessionBefore = vi.fn(async () => {})
+    const sessions = sessionState([summary('one', 2), summary('two', 1)])
+    const b = mount({
+      useSessions: hook(sessions),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['one', 'two'])])),
+      insertSessionBefore,
+    })
+    fireEvent.click(screen.getByText('alpha'))
+    const one = screen.getByText('one').closest('[role="treeitem"]') as HTMLElement
+    fireEvent.dragStart(one, { dataTransfer: { effectAllowed: '', dropEffect: '' } })
+    // The host dropped "one" from the workspace account while the drag is in
+    // flight: the source index is gone but the drop still resolves its anchor.
+    rerender(b, { useWorkspaces: hook(workspaceState([workspace('alpha', ['two'])])) })
+    const two = screen.getByText('two').closest('[role="treeitem"]') as HTMLElement
+    two.getBoundingClientRect = () => ({
+      top: 150, bottom: 184, left: 0, right: 200, width: 200, height: 34, x: 0, y: 150, toJSON: () => ({}),
+    } as DOMRect)
+    fireDrag(two, 'drop', 155)
+    expect(insertSessionBefore).toHaveBeenCalledWith(wid('alpha'), sid('one'), sid('two'))
+  })
+
+  it('drag end without a drop clears markers; bottom-half drop appends past the last row', () => {
+    const insertSessionBefore = vi.fn(async () => {})
+    const sessions = sessionState([summary('one', 2), summary('two', 1)])
+    mount({
+      useSessions: hook(sessions),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['one', 'two'])])),
+      insertSessionBefore,
+    })
+    fireEvent.click(screen.getByText('alpha'))
+    const [one, two] = screen.getAllByRole('treeitem').slice(1) as [HTMLElement, HTMLElement]
+    two.getBoundingClientRect = () => ({
+      top: 150, bottom: 184, left: 0, right: 200, width: 200, height: 34, x: 0, y: 150, toJSON: () => ({}),
+    } as DOMRect)
+    const dataTransfer = { effectAllowed: '', dropEffect: '' }
+    fireEvent.dragStart(one, { dataTransfer })
+    fireEvent.dragEnd(one)
+    // The drag ended: rows no longer accept drops.
+    fireDrag(two, 'drop', 180)
+    expect(insertSessionBefore).not.toHaveBeenCalled()
+
+    // Bottom half of the last row: append (anchor omitted).
+    fireEvent.dragStart(one, { dataTransfer })
+    fireDrag(two, 'dragOver', 180)
+    fireDrag(two, 'drop', 180)
+    expect(insertSessionBefore).toHaveBeenCalledWith(wid('alpha'), sid('one'), undefined)
+  })
+
+  it('logs and keeps the order when the reorder call rejects', async () => {
+    const warn = vi.spyOn(console, 'warn').mockImplementation(() => {})
+    try {
+      const insertSessionBefore = vi.fn(async () => { throw new Error('stale anchor') })
+      const sessions = sessionState([summary('one', 2), summary('two', 1)])
+      mount({
+        useSessions: hook(sessions),
+        useWorkspaces: hook(workspaceState([workspace('alpha', ['one', 'two'])])),
+        insertSessionBefore,
+      })
+      fireEvent.click(screen.getByText('alpha'))
+      const [one, two] = screen.getAllByRole('treeitem').slice(1) as [HTMLElement, HTMLElement]
+      two.getBoundingClientRect = () => ({
+        top: 150, bottom: 184, left: 0, right: 200, width: 200, height: 34, x: 0, y: 150, toJSON: () => ({}),
+      } as DOMRect)
+      const dataTransfer = { effectAllowed: '', dropEffect: '' }
+      fireEvent.dragStart(one, { dataTransfer })
+      fireDrag(two, 'drop', 180)
+      await waitFor(() => { expect(warn).toHaveBeenCalledWith('session reorder rejected:', expect.any(Error)) })
+    } finally {
+      warn.mockRestore()
+    }
+  })
+
+  it('renames a workspace through the row menu dialog', async () => {
+    let resolveRename!: () => void
+    const renameWorkspace = vi.fn(() => new Promise<void>((resolve) => { resolveRename = resolve }))
+    mount({
+      useWorkspaces: hook(workspaceState([workspace('alpha', [], 'Alpha'), workspace('beta', [], 'Beta')])),
+      renameWorkspace,
+    })
+    fireEvent.click(screen.getByRole('button', { name: 'Workspace actions for Alpha' }))
+    fireEvent.click(screen.getByRole('menuitem', { name: 'Rename' }))
+    const input = screen.getByLabelText<HTMLInputElement>('Workspace name')
+    expect(input.value).toBe('Alpha')
+    // Unchanged and blank names stay blocked.
+    expect((screen.getByRole('button', { name: 'Rename' }) as HTMLButtonElement).disabled).toBe(true)
+    fireEvent.change(input, { target: { value: '   ' } })
+    expect((screen.getByRole('button', { name: 'Rename' }) as HTMLButtonElement).disabled).toBe(true)
+    // A duplicate of another workspace's title shows the inline conflict.
+    fireEvent.change(input, { target: { value: ' Beta ' } })
+    expect(screen.getByRole('alert').textContent).toBe('A workspace named “Beta” already exists.')
+    expect((screen.getByRole('button', { name: 'Rename' }) as HTMLButtonElement).disabled).toBe(true)
+    fireEvent.change(input, { target: { value: 'Gamma' } })
+    fireEvent.click(screen.getByRole('button', { name: 'Rename' }))
+    expect(renameWorkspace).toHaveBeenCalledWith(wid('alpha'), 'Gamma')
+    // While renaming: input disabled, close blocked, Enter ignored.
+    expect(input.disabled).toBe(true)
+    fireEvent.keyDown(document, { key: 'Escape' })
+    expect(screen.getByRole('dialog')).toBeTruthy()
+    await act(async () => { resolveRename() })
+    expect(screen.queryByRole('dialog')).toBeNull()
+  })
+
+  it('rename via Enter, failure surfaces the error, Cancel closes', async () => {
+    const renameWorkspace = vi.fn(async () => { throw new Error('rename conflict') })
+    mount({
+      useWorkspaces: hook(workspaceState([workspace('alpha', [], 'Alpha')])),
+      renameWorkspace,
+    })
+    fireEvent.click(screen.getByRole('button', { name: 'Workspace actions for Alpha' }))
+    fireEvent.click(screen.getByRole('menuitem', { name: 'Rename' }))
+    const input = screen.getByLabelText<HTMLInputElement>('Workspace name')
+    // Enter with a blocked draft (unchanged) does nothing.
+    fireEvent.keyDown(input, { key: 'Enter' })
+    expect(renameWorkspace).not.toHaveBeenCalled()
+    fireEvent.change(input, { target: { value: 'Renamed' } })
+    fireEvent.keyDown(input, { key: 'a' })
+    fireEvent.keyDown(input, { key: 'Enter' })
+    expect(renameWorkspace).toHaveBeenCalledWith(wid('alpha'), 'Renamed')
+    await waitFor(() => { expect(screen.getByRole('alert').textContent).toBe('rename conflict') })
+    // The dialog stays for retry; typing clears the error; Cancel closes.
+    fireEvent.change(input, { target: { value: 'Renamed2' } })
+    expect(screen.queryByRole('alert')).toBeNull()
+    fireEvent.click(screen.getByRole('button', { name: 'Cancel' }))
+    expect(screen.queryByRole('dialog')).toBeNull()
+  })
+
+  it('reports non-Error rename failures as text', async () => {
+    const renameWorkspace = vi.fn(async () => { throw 'denied' })
+    mount({
+      useWorkspaces: hook(workspaceState([workspace('alpha', [], 'Alpha')])),
+      renameWorkspace,
+    })
+    fireEvent.click(screen.getByRole('button', { name: 'Workspace actions for Alpha' }))
+    fireEvent.click(screen.getByRole('menuitem', { name: 'Rename' }))
+    fireEvent.change(screen.getByLabelText('Workspace name'), { target: { value: 'Other' } })
+    fireEvent.click(screen.getByRole('button', { name: 'Rename' }))
+    await waitFor(() => { expect(screen.getByRole('alert').textContent).toBe('denied') })
+  })
+
+  it('search hides drag affordances (rows are not draggable during search)', () => {
+    const sessions = sessionState([summary('needle-a', 2, { displayTitle: 'Needle A' })])
+    mount({
+      useSessions: hook(sessions),
+      useWorkspaces: hook(workspaceState([workspace('alpha', ['needle-a'])])),
+    })
+    fireEvent.change(screen.getByPlaceholderText('Search name, keywords...'), { target: { value: 'needle' } })
+    const row = screen.getByText('Needle A').closest('[role="treeitem"]') as HTMLElement
+    expect(row.getAttribute('draggable')).toBe('false')
+  })
+})