feat(web): miller two-pane directory browser per the full figma flow

The single-column dialog missed the design's interaction model (figma
813-23126/813-23278, sibling frames of the linked node): selection is
not navigation. The browser now opens as one wide level; selecting a
row keeps it marked (pill + open-folder accent) and previews its
children in a second 256px column across a hairline divider, a
right-column pick advances one level, and the breadcrumb follows the
selection. New folder becomes the design's nested create dialog
("New folder in ...", Untitled-folder placeholder, Cancel/Create),
creating inside the selection and landing with the new folder selected.
Open adopts the selection, falling back to the listed level, so the
e2e path-edit flow is unchanged. The card is the design's fixed
600x420 with per-column scrolling.

packages/client/ui-workspace/src/client/DirectoryBrowser.module.css

@@ -1,13 +1,14 @@
-/* Directory-browser dialog (figma 802-56979). The shared Modal renders
+/* Directory-browser dialog (figma 813-23126 family). The shared Modal renders
  * headless here — mask, card, Escape only — and this module owns the figma
- * frame exactly: header (title + crumbs, l3 separator), one directory level,
- * and the bordered footer. Card: w600 r24, bottom pad 12, no close chrome. */
+ * frame exactly: fixed 600×420 card, header (title + crumbs, l3 separator),
+ * the one-or-two-column Miller content, and the bordered footer. */
 
 /* Doubled class beats Modal's own .dialog regardless of stylesheet order. */
 .dialog.dialog {
   width: min(600px, 100%);
-  padding: 0 0 12px;
-  gap: 16px;
+  height: 420px;
+  padding: 0;
+  gap: 0;
 }
 
 /* Header block: pl24 pr14 pt22 pb12, 8px between title row and crumb row. */
@@ -15,6 +16,7 @@
   display: flex;
   flex-direction: column;
   gap: 8px;
+  flex: none;
   padding: 22px 14px 12px 24px;
   border-bottom: 1px solid var(--dsw-alias-border-l3);
 }
@@ -95,16 +97,37 @@
   color: var(--dsw-alias-label-primary);
 }
 
-/* One directory level: content column pt16 px24, 28px rows with 2px gaps. */
-.level {
+/* Miller content: pt16 px24; columns are 256 wide (or full width solo) with
+ * the hairline divider centered between them; each column scrolls alone. */
+.content {
+  display: flex;
+  align-items: stretch;
+  flex: 1 1 0;
+  min-height: 0;
+  gap: 20px;
+  padding: 16px 24px 0;
+}
+
+.column {
   display: flex;
   flex-direction: column;
   gap: 2px;
-  padding: 16px 24px 0;
-  max-height: 320px;
+  width: 256px;
+  flex: none;
   overflow-y: auto;
 }
 
+.columnWide {
+  width: 100%;
+  flex: 1 1 0;
+}
+
+.divider {
+  flex: none;
+  width: 1px;
+  background: var(--dsw-alias-border-l3);
+}
+
 .row {
   display: flex;
   align-items: center;
@@ -123,11 +146,22 @@
   background: var(--dsw-alias-interactive-bg-hover);
 }
 
+/* Selection: pill fill + the open-folder glyph in the info accent. */
+.rowSelected,
+.rowSelected:hover {
+  background: var(--dsw-alias-interactive-bg-active, var(--dsw-alias-interactive-bg-hover));
+}
+
 .rowIcon {
   flex: none;
   color: var(--dsw-alias-label-secondary);
 }
 
+.rowIconSelected {
+  flex: none;
+  color: var(--dsw-alias-button-info-fill);
+}
+
 .rowName {
   flex: 1 1 0;
   min-width: 0;
@@ -145,29 +179,6 @@
   color: var(--dsw-alias-label-tertiary);
 }
 
-.folderRow {
-  cursor: default;
-}
-
-.folderInput {
-  box-sizing: border-box;
-  flex: 1 1 0;
-  min-width: 0;
-  height: 24px;
-  padding: 0 6px;
-  border: 1px solid var(--dsw-alias-border-l2);
-  border-radius: 6px;
-  outline: none;
-  background: transparent;
-  font-size: 13px;
-  line-height: 20px;
-  color: var(--dsw-alias-label-primary);
-}
-
-.folderInput::placeholder {
-  color: var(--dsw-alias-label-caption);
-}
-
 .status,
 .error {
   padding: 4px;
@@ -183,12 +194,14 @@
   color: var(--dsw-alias-state-error-primary);
 }
 
-/* Footer: l3 separator on top, pt12 px24, New-folder pinned left. */
+/* Footer: l3 separator on top, pt12 px24, New-folder pinned left; the fixed
+ * card leaves the figma 28px below the 36px buttons. */
 .footerBar {
   display: flex;
   align-items: center;
   gap: 8px;
-  padding: 12px 24px 0;
+  flex: none;
+  padding: 12px 24px 28px;
   border-top: 1px solid var(--dsw-alias-border-l3);
 }
 
@@ -199,3 +212,58 @@
 .footerAction {
   min-width: 72px;
 }
+
+/* Nested create dialog (figma 813:23278): a small centered card. */
+.createDialog.createDialog {
+  width: min(380px, 100%);
+  padding: 0;
+  gap: 0;
+}
+
+.createBody {
+  display: flex;
+  flex-direction: column;
+  gap: 12px;
+  padding: 22px 24px 20px;
+}
+
+.createTitle {
+  margin: 0;
+  font-size: 16px;
+  line-height: 24px;
+  font-weight: 510;
+  color: var(--dsw-alias-label-primary);
+}
+
+.createIn {
+  margin: 0;
+  font-size: 14px;
+  line-height: 22px;
+  color: var(--dsw-alias-label-primary);
+}
+
+.createInput {
+  box-sizing: border-box;
+  width: 100%;
+  height: 44px;
+  padding: 7px 14px;
+  border: 1px solid var(--dsw-alias-border-l2);
+  border-radius: 22px;
+  outline: none;
+  background: transparent;
+  font-size: 14px;
+  line-height: 22px;
+  color: var(--dsw-alias-label-primary);
+}
+
+.createInput::placeholder {
+  color: var(--dsw-alias-label-caption);
+}
+
+.createActions {
+  display: flex;
+  align-items: center;
+  justify-content: flex-end;
+  gap: 8px;
+  margin-top: 8px;
+}

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

@@ -1,15 +1,21 @@
 /**
- * The in-app workspace-directory browser (figma Harness 802-56979): breadcrumb
- * header with a click-to-edit path zone, one navigable directory level, an
- * inline New-folder row, and the Cancel/Open footer. Pure consumer of the
- * injected browse calls — the owning flow decides what "Open" means and owns
- * the workspace-creation error surface. Hidden entries are host-flagged and
- * filtered here (a show-hidden toggle is deferred work, client-side only).
+ * The in-app workspace-directory browser (figma Harness 813-23126 family): a
+ * fixed 600×420 dialog whose header carries the title, the selection-path
+ * breadcrumb, and a click-to-edit path zone; below it a Miller view — one
+ * full-width level until a row is selected, then two 256px columns (level |
+ * selected folder's children) around a hairline divider. Selecting in the
+ * right column shifts the view one level deeper. "New folder" opens a nested
+ * create dialog targeting the selected folder (or the level itself) and
+ * selects the created folder. Open adopts the selected folder, falling back
+ * to the listed level. Pure consumer of the injected browse calls — the
+ * owning flow decides what "Open" means and owns the workspace-creation
+ * error surface. Hidden entries are host-flagged and filtered here (a
+ * show-hidden toggle is deferred work, client-side only).
  */
 import { useCallback, useEffect, useRef, useState } from 'react'
 import clsx from 'clsx'
 import {
-  Button, IconChevronRightOutline14, IconFolderClose16, IconPlusOutline16, Modal,
+  Button, IconChevronRightOutline14, IconFolderClose16, IconFolderOpen16, IconPlusOutline16, Modal,
 } from '@deepseek-ai/dsh-client-ui-primitives'
 import type { DirectoryEntry, DirectoryListing } from '@deepseek-ai/dsh-client-runtime/client'
 import { DirectoryBrowseError } from '@deepseek-ai/dsh-client-runtime/client'
@@ -22,13 +28,13 @@ export interface DirectoryBrowserProps {
   open: boolean
   /** List one directory level (absent path = the Host home directory). */
   listDirectory: (path?: string) => Promise<DirectoryListing>
-  /** Create one child directory under the listed level. */
+  /** Create one child directory under an existing parent. */
   createDirectory: (path: string, name: string) => Promise<string>
-  /** The operator confirmed the currently listed directory. */
+  /** The operator confirmed a directory (the selection, else the listed level). */
   onOpen: (path: string) => void
   /** Close without picking (mask, Escape, Cancel). */
   onClose: () => void
-  /** The owner's confirm is in flight: Open disables, the level freezes. */
+  /** The owner's confirm is in flight: Open disables, the view freezes. */
   busy: boolean
   /** Localized copy. */
   t: Translate
@@ -52,32 +58,73 @@ function displayCrumbs(listing: DirectoryListing, homeLabel: string): DirectoryE
   return [{ name: homeLabel, path: listing.home, hidden: false }, ...tail]
 }
 
+/** One column of folder rows (the Miller view renders one or two of these). */
+function LevelColumn({ entries, selectedPath, busy, onPick, wide }: {
+  entries: readonly DirectoryEntry[]
+  selectedPath: string | null
+  busy: boolean
+  onPick: (entry: DirectoryEntry) => void
+  wide: boolean
+}) {
+  return (
+    <div className={clsx(css.column, wide && css.columnWide)} role="list">
+      {entries.filter(entry => !entry.hidden).map((entry) => {
+        const selected = entry.path === selectedPath
+        return (
+          <button
+            key={entry.path}
+            type="button"
+            role="listitem"
+            aria-current={selected || undefined}
+            className={clsx(css.row, selected && css.rowSelected)}
+            disabled={busy}
+            onClick={() => { onPick(entry) }}
+          >
+            {selected
+              ? <IconFolderOpen16 size={16} className={css.rowIconSelected} />
+              : <IconFolderClose16 size={16} className={css.rowIcon} />}
+            <span className={css.rowName}>{entry.name}</span>
+            <IconChevronRightOutline14 size={12} className={css.rowChevron} />
+          </button>
+        )
+      })}
+    </div>
+  )
+}
+
 /**
  * Render the directory-browser dialog.
  * @param props - owner-controlled browser props.
  * @returns the dialog element (null while closed, via Modal).
  */
 export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen, onClose, busy, t }: DirectoryBrowserProps) {
-  const [listing, setListing] = useState<DirectoryListing | null>(null)
+  // Miller state: the listed level, the selected row in it, and the selected
+  // folder's own listing (the right column; null while nothing is selected).
+  const [parent, setParent] = useState<DirectoryListing | null>(null)
+  const [selected, setSelected] = useState<DirectoryEntry | null>(null)
+  const [child, setChild] = useState<DirectoryListing | null>(null)
   const [loading, setLoading] = useState(false)
   const [error, setError] = useState<string | null>(null)
   // Path-edit state: null = breadcrumb mode; a string = the draft being typed.
   const [pathDraft, setPathDraft] = useState<string | null>(null)
-  // New-folder state: null = no inline row; a string = the name being typed.
+  // Create-folder state: null = closed; a string = the nested dialog's draft.
   const [folderDraft, setFolderDraft] = useState<string | null>(null)
   const [creatingFolder, setCreatingFolder] = useState(false)
+  const [createError, setCreateError] = useState<string | null>(null)
   const requestSeq = useRef(0)
 
+  /** Replace the whole view with one freshly listed level (no selection). */
   const navigate = useCallback((path?: string) => {
     const seq = ++requestSeq.current
     setLoading(true)
     setError(null)
     listDirectory(path).then((next) => {
       if (seq !== requestSeq.current) return
-      setListing(next)
+      setParent(next)
+      setSelected(null)
+      setChild(null)
       setLoading(false)
       setPathDraft(null)
-      setFolderDraft(null)
     }, (reason: unknown) => {
       if (seq !== requestSeq.current) return
       setLoading(false)
@@ -85,11 +132,39 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
     })
   }, [listDirectory])
 
+  /** Select a row of the listed level and preview its children on the right. */
+  const select = useCallback((entry: DirectoryEntry) => {
+    const seq = ++requestSeq.current
+    setSelected(entry)
+    setChild(null)
+    setLoading(true)
+    setError(null)
+    listDirectory(entry.path).then((next) => {
+      if (seq !== requestSeq.current) return
+      setChild(next)
+      setLoading(false)
+    }, (reason: unknown) => {
+      if (seq !== requestSeq.current) return
+      setLoading(false)
+      setError(failureText(reason))
+    })
+  }, [listDirectory])
+
+  /** A right-column pick advances the view one level: child becomes the level. */
+  const advance = useCallback((entry: DirectoryEntry) => {
+    /* v8 ignore next -- narrowing guard: the right column only renders with a child listing. */
+    if (child === null) return
+    setParent(child)
+    select(entry)
+  }, [child, select])
+
   // Every open starts fresh at the Host home directory; closing invalidates
   // any in-flight response so a late arrival cannot repopulate a closed dialog.
   useEffect(() => {
     if (open) {
-      setListing(null)
+      setParent(null)
+      setSelected(null)
+      setChild(null)
       navigate()
       return
     }
@@ -97,29 +172,56 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
     setError(null)
     setPathDraft(null)
     setFolderDraft(null)
+    setCreateError(null)
   }, [open, navigate])
 
-  const confirmFolder = (): void => {
-    /* v8 ignore next -- reentry fence: the inline row only renders with a listing and a draft, and the input disables while creating. */
-    if (listing === null || folderDraft === null || creatingFolder) return
+  /** The folder a create or Open acts on: the selection, else the listed level. */
+  const targetPath = selected?.path ?? parent?.path ?? null
+  const targetName = selected?.name
+    ?? (parent === null ? '' : (displayCrumbs(parent, t('browser.home')).at(-1)?.name ?? parent.path))
+
+  const confirmCreate = (): void => {
+    /* v8 ignore next -- reentry fence: the nested dialog only renders with a target and disables while creating. */
+    if (targetPath === null || folderDraft === null || creatingFolder) return
     const name = folderDraft.trim()
     if (name === '') return
     setCreatingFolder(true)
-    setError(null)
-    createDirectory(listing.path, name).then(() => {
+    setCreateError(null)
+    createDirectory(targetPath, name).then((createdPath) => {
       setCreatingFolder(false)
       setFolderDraft(null)
-      navigate(listing.path)
+      // Land like a right-column pick (figma 802:57446 → 813:23278 flow): the
+      // create target becomes the listed level and the new folder its selection.
+      const seq = ++requestSeq.current
+      setLoading(true)
+      listDirectory(targetPath).then((level) => {
+        // Same seq fence as navigate/select; the nested dialog blocks
+        // superseding input during this relist.
+        /* v8 ignore next */
+        if (seq !== requestSeq.current) return
+        setParent(level)
+        setLoading(false)
+        select({ name, path: createdPath, hidden: false })
+      }, (reason: unknown) => {
+        // Same seq fence as navigate/select; the nested dialog blocks
+        // superseding input during this relist.
+        /* v8 ignore next */
+        if (seq !== requestSeq.current) return
+        setLoading(false)
+        setError(failureText(reason))
+      })
     }, (reason: unknown) => {
       setCreatingFolder(false)
-      setError(failureText(reason))
+      setCreateError(failureText(reason))
     })
   }
 
   // After the hooks: a closed dialog renders nothing and evaluates no copy.
   if (!open) return null
 
-  const crumbs = listing === null ? [] : displayCrumbs(listing, t('browser.home'))
+  const crumbSource = child ?? parent
+  const crumbs = crumbSource === null ? [] : displayCrumbs(crumbSource, t('browser.home'))
+  const twoPane = selected !== null
 
   return (
     <Modal
@@ -153,9 +255,9 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
                   type="button"
                   className={css.crumbEditZone}
                   aria-label={t('browser.editPath')}
-                  disabled={listing === null || busy}
-                  /* v8 ignore next -- narrowing guard: the zone disables while the listing is null. */
-                  onClick={() => { if (listing !== null) setPathDraft(listing.path) }}
+                  disabled={parent === null || busy}
+                  /* v8 ignore next -- narrowing guard: the zone disables while the level is null. */
+                  onClick={() => { if (parent !== null) setPathDraft(selected?.path ?? parent.path) }}
                 />
               </>
             )
@@ -183,45 +285,26 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
             )}
         </div>
       </div>
-      <div className={css.level} role="list" aria-label={t('browser.title')}>
-        {folderDraft !== null && listing !== null && (
-          <div className={clsx(css.row, css.folderRow)}>
-            <IconFolderClose16 size={16} className={css.rowIcon} />
-            <input
-              className={css.folderInput}
-              value={folderDraft}
-              aria-label={t('browser.newFolder')}
-              placeholder={t('browser.folderName')}
-              autoFocus
-              disabled={creatingFolder}
-              onChange={(event) => { setFolderDraft(event.target.value) }}
-              onKeyDown={(event) => {
-                if (event.key === 'Enter') {
-                  event.preventDefault()
-                  confirmFolder()
-                }
-                if (event.key === 'Escape') {
-                  event.stopPropagation()
-                  setFolderDraft(null)
-                }
-              }}
-            />
-          </div>
+      <div className={css.content}>
+        {parent !== null && (
+          <LevelColumn
+            entries={parent.entries}
+            selectedPath={selected?.path ?? null}
+            busy={busy}
+            onPick={select}
+            wide={!twoPane}
+          />
+        )}
+        {twoPane && <span className={css.divider} />}
+        {twoPane && child !== null && (
+          <LevelColumn
+            entries={child.entries}
+            selectedPath={null}
+            busy={busy}
+            onPick={advance}
+            wide={false}
+          />
         )}
-        {listing?.entries.filter(entry => !entry.hidden).map(entry => (
-          <button
-            key={entry.path}
-            type="button"
-            role="listitem"
-            className={css.row}
-            disabled={busy}
-            onClick={() => { navigate(entry.path) }}
-          >
-            <IconFolderClose16 size={16} className={css.rowIcon} />
-            <span className={css.rowName}>{entry.name}</span>
-            <IconChevronRightOutline14 size={12} className={css.rowChevron} />
-          </button>
-        ))}
         {loading && <div className={css.status} role="status">{t('browser.loading')}</div>}
         {error !== null && <div className={css.error} role="alert">{error}</div>}
       </div>
@@ -229,8 +312,11 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
         <Button
           variant="outline"
           icon={<IconPlusOutline16 size={14} />}
-          disabled={listing === null || busy || folderDraft !== null}
-          onClick={() => { setFolderDraft('') }}
+          disabled={parent === null || busy || folderDraft !== null}
+          onClick={() => {
+            setFolderDraft('')
+            setCreateError(null)
+          }}
         >
           {t('browser.newFolder')}
         </Button>
@@ -239,13 +325,56 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
         <Button
           variant="primary"
           className={clsx(css.footerAction)}
-          disabled={listing === null || loading || busy}
-          /* v8 ignore next -- narrowing guard: Open disables while the listing is null. */
-          onClick={() => { if (listing !== null) onOpen(listing.path) }}
+          disabled={targetPath === null || loading || busy}
+          /* v8 ignore next -- narrowing guard: Open disables while no target exists. */
+          onClick={() => { if (targetPath !== null) onOpen(targetPath) }}
         >
           {t('browser.open')}
         </Button>
       </div>
+      {/* Nested create dialog (figma 813:23278): names one folder inside the target. */}
+      <Modal
+        open={folderDraft !== null}
+        onClose={() => { if (!creatingFolder) setFolderDraft(null) }}
+        title={t('browser.newFolder')}
+        className={clsx(css.createDialog)}
+        headless
+      >
+        <div className={css.createBody}>
+          <h3 className={css.createTitle}>{t('browser.newFolder')}</h3>
+          <p className={css.createIn}>{t('browser.createIn', { name: targetName })}</p>
+          <input
+            className={css.createInput}
+            value={folderDraft ?? ''}
+            aria-label={t('browser.folderName')}
+            placeholder={t('browser.untitledFolder')}
+            autoFocus
+            disabled={creatingFolder}
+            onChange={(event) => { setFolderDraft(event.target.value) }}
+            onKeyDown={(event) => {
+              if (event.key === 'Enter') {
+                event.preventDefault()
+                confirmCreate()
+              }
+              if (event.key === 'Escape') {
+                event.stopPropagation()
+                if (!creatingFolder) setFolderDraft(null)
+              }
+            }}
+          />
+          {createError !== null && <div className={css.error} role="alert">{createError}</div>}
+          <div className={css.createActions}>
+            <Button variant="outline" disabled={creatingFolder} onClick={() => { setFolderDraft(null) }}>{t('browser.cancel')}</Button>
+            <Button
+              variant="primary"
+              disabled={creatingFolder || folderDraft === null || folderDraft.trim() === ''}
+              onClick={confirmCreate}
+            >
+              {t('browser.create')}
+            </Button>
+          </div>
+        </div>
+      </Modal>
     </Modal>
   )
 }

packages/client/ui-workspace/src/client/index.ts

@@ -44,6 +44,9 @@ export function apply(ctx: ClientContext): void {
         'browser.home': '主目录',
         'browser.newFolder': '新建文件夹',
         'browser.folderName': '文件夹名称',
+        'browser.createIn': '在"{name}"中新建文件夹',
+        'browser.untitledFolder': '未命名文件夹',
+        'browser.create': '创建',
         'browser.cancel': '取消',
         'browser.open': '打开',
         'browser.editPath': '编辑路径',
@@ -54,6 +57,9 @@ export function apply(ctx: ClientContext): void {
         'browser.home': 'Home',
         'browser.newFolder': 'New folder',
         'browser.folderName': 'Folder name',
+        'browser.createIn': 'New folder in "{name}"',
+        'browser.untitledFolder': 'Untitled folder',
+        'browser.create': 'Create',
         'browser.cancel': 'Cancel',
         'browser.open': 'Open',
         'browser.editPath': 'Edit path',

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

@@ -1,6 +1,6 @@
 // @vitest-environment jsdom
 import { afterEach, describe, expect, it, vi } from 'vitest'
-import { cleanup, fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { cleanup, fireEvent, render, screen, waitFor, within } from '@testing-library/react'
 import type { DirectoryListing } from '@deepseek-ai/dsh-client-runtime/client'
 import { DirectoryBrowseError } from '@deepseek-ai/dsh-client-runtime/client'
 import { DirectoryBrowser } from '../src/client/DirectoryBrowser.tsx'
@@ -8,6 +8,8 @@ import { DirectoryBrowser } from '../src/client/DirectoryBrowser.tsx'
 afterEach(cleanup)
 
 const HOME = '/home/u'
+const DOCS = `${HOME}/Documents`
+const HARNESS = `${DOCS}/harness`
 
 /** Listing fake over a tiny fixed tree; unknown paths reject like the Host. */
 function listingFor(path?: string): DirectoryListing {
@@ -23,19 +25,31 @@ function listingFor(path?: string): DirectoryListing {
       ],
       entries: [
         { name: '.config', path: `${HOME}/.config`, hidden: true },
-        { name: 'Documents', path: `${HOME}/Documents`, hidden: false },
+        { name: 'Documents', path: DOCS, hidden: false },
       ],
     },
-    [`${HOME}/Documents`]: {
-      path: `${HOME}/Documents`,
+    [DOCS]: {
+      path: DOCS,
       home: HOME,
       crumbs: [
         { name: '/', path: '/', hidden: false },
         { name: 'home', path: '/home', hidden: false },
         { name: 'u', path: HOME, hidden: false },
-        { name: 'Documents', path: `${HOME}/Documents`, hidden: false },
+        { name: 'Documents', path: DOCS, hidden: false },
       ],
-      entries: [{ name: 'harness', path: `${HOME}/Documents/harness`, hidden: false }],
+      entries: [{ name: 'harness', path: HARNESS, hidden: false }],
+    },
+    [HARNESS]: {
+      path: HARNESS,
+      home: HOME,
+      crumbs: [
+        { name: '/', path: '/', hidden: false },
+        { name: 'home', path: '/home', hidden: false },
+        { name: 'u', path: HOME, hidden: false },
+        { name: 'Documents', path: DOCS, hidden: false },
+        { name: 'harness', path: HARNESS, hidden: false },
+      ],
+      entries: [],
     },
   }
   const found = tree[target]
@@ -57,49 +71,102 @@ function mount(overrides: Partial<Parameters<typeof DirectoryBrowser>[0]> = {})
     onOpen,
     onClose,
     busy: false,
-    t: (key: string) => key,
+    t: (key: string, params?: Record<string, unknown>) => (params === undefined ? key : `${key}:${String(params.name)}`),
     ...overrides,
   }
   const view = render(<DirectoryBrowser {...props} />)
   return { view, props, listDirectory, createDirectory, onOpen, onClose }
 }
 
+/** The rendered level columns, left-to-right. */
+function columns(): HTMLElement[] {
+  return screen.getAllByRole('list')
+}
+
 describe('DirectoryBrowser', () => {
-  it('opens at the Host home, hides hidden entries, and roots the crumbs at Home', async () => {
+  it('opens at the Host home as one wide column, hides hidden entries, and roots the crumbs at Home', async () => {
     const b = mount()
     await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
     expect(b.listDirectory).toHaveBeenCalledWith(undefined)
+    expect(columns()).toHaveLength(1)
     expect(screen.getByRole('listitem').textContent).toBe('Documents')
     expect(screen.queryByText('.config')).toBeNull()
-    // Inside the home subtree the chain collapses to a localized Home crumb.
     expect(screen.getByRole('button', { name: 'browser.home' })).toBeTruthy()
     expect(screen.queryByRole('button', { name: '/' })).toBeNull()
   })
 
-  it('enters a row on click and jumps back through a crumb', async () => {
+  it('selects a row into the two-pane view: children preview right, crumbs follow the selection', async () => {
     const b = mount()
     await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
     fireEvent.click(screen.getByRole('listitem'))
-    await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('harness') })
-    expect(b.listDirectory).toHaveBeenLastCalledWith(`${HOME}/Documents`)
-    fireEvent.click(screen.getByRole('button', { name: 'browser.home' }))
-    await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('Documents') })
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
+    const [level, preview] = columns()
+    const selectedRow = within(level!).getByRole('listitem')
+    expect(selectedRow.textContent).toBe('Documents')
+    expect(selectedRow.getAttribute('aria-current')).toBe('true')
+    expect(within(preview!).getByRole('listitem').textContent).toBe('harness')
+    expect(b.listDirectory).toHaveBeenLastCalledWith(DOCS)
+    expect(screen.getByRole('button', { name: 'Documents' })).toBeTruthy()
   })
 
-  it('edits the path from the crumb bar: Enter navigates, Escape restores', async () => {
+  it('advances one level when a right-column row is picked', async () => {
     mount()
     await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(screen.getByRole('listitem'))
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
+    fireEvent.click(within(columns()[1]!).getByRole('listitem'))
+    await waitFor(() => { expect(screen.getByRole('button', { name: 'harness' })).toBeTruthy() })
+    const [level] = columns()
+    const selectedRow = within(level!).getByRole('listitem')
+    expect(selectedRow.textContent).toBe('harness')
+    expect(selectedRow.getAttribute('aria-current')).toBe('true')
+  })
+
+  it('jumps back through a crumb into a fresh single-column level', async () => {
+    mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(screen.getByRole('listitem'))
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
+    fireEvent.click(screen.getByRole('button', { name: 'browser.home' }))
+    await waitFor(() => { expect(columns()).toHaveLength(1) })
+    expect(screen.getByRole('listitem').textContent).toBe('Documents')
+    expect(screen.getByRole('listitem').getAttribute('aria-current')).toBeNull()
+  })
+
+  it('opens the selection, else the listed level; Cancel closes; busy freezes Open', async () => {
+    const b = mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(screen.getByRole('button', { name: 'browser.open' }))
+    expect(b.onOpen).toHaveBeenCalledWith(HOME)
+    fireEvent.click(screen.getByRole('listitem'))
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
+    fireEvent.click(screen.getByRole('button', { name: 'browser.open' }))
+    expect(b.onOpen).toHaveBeenLastCalledWith(DOCS)
+    fireEvent.click(screen.getByRole('button', { name: 'browser.cancel' }))
+    expect(b.onClose).toHaveBeenCalled()
+
+    const busy = mount({ busy: true })
+    await waitFor(() => { expect(busy.listDirectory).toHaveBeenCalled() })
+    expect(screen.getAllByRole<HTMLButtonElement>('button', { name: 'browser.open' }).at(-1)!.disabled).toBe(true)
+  })
+
+  it('edits the path from the crumb bar: Enter navigates, Escape restores, blank is ignored', async () => {
+    const b = mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
     fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
     const input = screen.getByLabelText<HTMLInputElement>('browser.editPath')
     expect(input.value).toBe(HOME)
-    fireEvent.change(input, { target: { value: `${HOME}/Documents` } })
+    fireEvent.change(input, { target: { value: DOCS } })
     fireEvent.keyDown(input, { key: 'Enter' })
     await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('harness') })
-    // Escape leaves an opened edit without navigating.
+    expect(columns()).toHaveLength(1)
     fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
-    fireEvent.keyDown(screen.getByLabelText('browser.editPath'), { key: 'Escape' })
+    const again = screen.getByLabelText<HTMLInputElement>('browser.editPath')
+    fireEvent.change(again, { target: { value: '   ' } })
+    fireEvent.keyDown(again, { key: 'Enter' })
+    expect(b.listDirectory).toHaveBeenCalledTimes(2)
+    fireEvent.keyDown(again, { key: 'Escape' })
     expect(screen.queryByLabelText('browser.editPath', { selector: 'input' })).toBeNull()
-    expect(screen.getByRole('listitem').textContent).toBe('harness')
   })
 
   it('surfaces an unreadable target as an alert and keeps the edit open for correction', async () => {
@@ -114,40 +181,16 @@ describe('DirectoryBrowser', () => {
     expect(screen.getByRole('listitem').textContent).toBe('Documents')
   })
 
-  it('creates a folder inline and refreshes the level; failures land as alerts', async () => {
-    const b = mount()
-    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
-    fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
-    const input = screen.getByLabelText('browser.newFolder')
-    fireEvent.change(input, { target: { value: 'fresh' } })
-    fireEvent.keyDown(input, { key: 'Enter' })
-    await waitFor(() => { expect(b.createDirectory).toHaveBeenCalledWith(HOME, 'fresh') })
-    // The level reloads after creation (initial + post-create).
-    await waitFor(() => { expect(b.listDirectory).toHaveBeenLastCalledWith(HOME) })
-
-    b.createDirectory.mockRejectedValueOnce(
-      new DirectoryBrowseError({ code: 'directory-exists', message: 'taken already', details: { path: `${HOME}/x` } }))
-    fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
-    const retry = screen.getByLabelText('browser.newFolder')
-    fireEvent.change(retry, { target: { value: 'x' } })
-    fireEvent.keyDown(retry, { key: 'Enter' })
-    await waitFor(() => { expect(screen.getByRole('alert').textContent).toBe('taken already') })
+  it('folds non-typed failures into readable text (Error message, String otherwise)', async () => {
+    const b = mount({ listDirectory: vi.fn(async () => { throw new Error('socket down') }) })
+    await waitFor(() => { expect(screen.getByRole('alert').textContent).toBe('socket down') })
+    b.view.rerender(<DirectoryBrowser {...b.props} open={false} />)
+    const raw = mount({ listDirectory: vi.fn(async () => { throw 'raw failure' }) })
+    await waitFor(() => { expect(screen.getAllByRole('alert').at(-1)!.textContent).toBe('raw failure') })
+    expect(raw.onOpen).not.toHaveBeenCalled()
   })
 
-  it('confirms the listed directory through Open, closes through Cancel, and freezes while busy', async () => {
-    const b = mount()
-    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
-    fireEvent.click(screen.getByRole('button', { name: 'browser.open' }))
-    expect(b.onOpen).toHaveBeenCalledWith(HOME)
-    fireEvent.click(screen.getByRole('button', { name: 'browser.cancel' }))
-    expect(b.onClose).toHaveBeenCalled()
-
-    const busy = mount({ busy: true })
-    await waitFor(() => { expect(busy.listDirectory).toHaveBeenCalled() })
-    expect(screen.getAllByRole<HTMLButtonElement>('button', { name: 'browser.open' }).at(-1)!.disabled).toBe(true)
-  })
-
-  it('renders the full ancestry when the listing sits outside the home subtree', async () => {
+  it('renders the full ancestry when the level sits outside the home subtree', async () => {
     const outside: DirectoryListing = {
       path: '/srv/data',
       home: HOME,
@@ -164,53 +207,110 @@ describe('DirectoryBrowser', () => {
     expect(screen.queryByRole('button', { name: 'browser.home' })).toBeNull()
   })
 
-  it('folds non-typed failures into readable text (Error message, String otherwise)', async () => {
-    const b = mount({ listDirectory: vi.fn(async () => { throw new Error('socket down') }) })
-    await waitFor(() => { expect(screen.getByRole('alert').textContent).toBe('socket down') })
-    b.view.rerender(<DirectoryBrowser {...b.props} open={false} />)
-    const raw = mount({ listDirectory: vi.fn(async () => { throw 'raw failure' }) })
-    await waitFor(() => { expect(screen.getAllByRole('alert').at(-1)!.textContent).toBe('raw failure') })
-    expect(raw.onOpen).not.toHaveBeenCalled()
-  })
-
-  it('cancels the inline folder row with Escape and ignores a blank name', async () => {
+  it('creates a folder through the nested dialog and lands with it selected', async () => {
     const b = mount()
     await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(screen.getByRole('listitem'))
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
     fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
-    const input = screen.getByLabelText('browser.newFolder')
+    // The nested dialog names the create target (the selected folder).
+    expect(screen.getByText('browser.createIn:Documents')).toBeTruthy()
+    // The created folder becomes listable (like the real backend after mkdir).
+    b.listDirectory.mockImplementation(async (path?: string) => {
+      if (path === `${DOCS}/fresh`) {
+        return {
+          path: `${DOCS}/fresh`, home: HOME,
+          crumbs: [...listingFor(DOCS).crumbs, { name: 'fresh', path: `${DOCS}/fresh`, hidden: false }],
+          entries: [],
+        }
+      }
+      if (path === DOCS) {
+        const docs = listingFor(DOCS)
+        return { ...docs, entries: [...docs.entries, { name: 'fresh', path: `${DOCS}/fresh`, hidden: false }] }
+      }
+      return listingFor(path)
+    })
+    const input = screen.getByLabelText('browser.folderName')
+    fireEvent.change(input, { target: { value: 'fresh' } })
+    fireEvent.keyDown(input, { key: 'Enter' })
+    await waitFor(() => { expect(b.createDirectory).toHaveBeenCalledWith(DOCS, 'fresh') })
+    // The create target became the level and the new folder its selection.
+    await waitFor(() => {
+      expect(screen.getByRole('button', { name: 'Documents' })).toBeTruthy()
+      const level = columns()[0]!
+      const rows = within(level).getAllByRole('listitem')
+      expect(rows.some(row => row.textContent === 'fresh' && row.getAttribute('aria-current') === 'true')).toBe(true)
+    })
+  })
+
+  it('keeps the nested dialog open on a creation failure and cancels cleanly', async () => {
+    const b = mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    b.createDirectory.mockRejectedValueOnce(
+      new DirectoryBrowseError({ code: 'directory-exists', message: 'taken already', details: { path: `${HOME}/x` } }))
+    fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
+    expect(screen.getByText('browser.createIn:browser.home')).toBeTruthy()
+    const input = screen.getByLabelText('browser.folderName')
+    // A blank name never submits.
     fireEvent.change(input, { target: { value: '   ' } })
     fireEvent.keyDown(input, { key: 'Enter' })
     expect(b.createDirectory).not.toHaveBeenCalled()
-    fireEvent.keyDown(input, { key: 'Escape' })
-    expect(screen.queryByLabelText('browser.newFolder')).toBeNull()
-  })
-
-  it('ignores a blank path draft on Enter', async () => {
-    const b = mount()
-    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
-    fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
-    const input = screen.getByLabelText('browser.editPath')
-    fireEvent.change(input, { target: { value: '   ' } })
+    fireEvent.change(input, { target: { value: 'x' } })
     fireEvent.keyDown(input, { key: 'Enter' })
-    // Only the initial home listing ran; the blank draft navigated nowhere.
-    expect(b.listDirectory).toHaveBeenCalledTimes(1)
+    await waitFor(() => { expect(screen.getByRole('alert').textContent).toBe('taken already') })
+    fireEvent.keyDown(screen.getByLabelText('browser.folderName'), { key: 'Escape' })
+    await waitFor(() => { expect(screen.queryByLabelText('browser.folderName')).toBeNull() })
+
+    // The nested Cancel button and the nested mask both close only the child dialog.
+    fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
+    const nested = screen.getByRole('dialog', { name: 'browser.newFolder' })
+    fireEvent.click(within(nested).getByRole('button', { name: 'browser.cancel' }))
+    await waitFor(() => { expect(screen.queryByLabelText('browser.folderName')).toBeNull() })
+    fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
+    const masks = document.querySelectorAll('[aria-hidden="true"]')
+    fireEvent.click(masks[masks.length - 1]!)
+    await waitFor(() => { expect(screen.queryByLabelText('browser.folderName')).toBeNull() })
+    expect(screen.getByRole('dialog', { name: 'browser.title' })).toBeTruthy()
   })
 
-  it('drops a stale listing that resolves after a newer navigation', async () => {
+  it('surfaces a selection-preview failure while keeping the selection marked', async () => {
+    const b = mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    b.listDirectory.mockRejectedValueOnce(
+      new DirectoryBrowseError({ code: 'directory-unreadable', message: 'denied', details: { path: DOCS } }))
+    fireEvent.click(screen.getByRole('listitem'))
+    await waitFor(() => { expect(screen.getByRole('alert').textContent).toBe('denied') })
+    expect(screen.getByRole('listitem').getAttribute('aria-current')).toBe('true')
+    // No preview column arrived for the failed selection.
+    expect(columns()).toHaveLength(1)
+  })
+
+  it('surfaces a post-create relist failure on the browser surface', async () => {
+    const b = mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
+    // Creation succeeds, but relisting the target fails afterwards.
+    b.listDirectory.mockRejectedValueOnce(new Error('level vanished'))
+    const input = screen.getByLabelText('browser.folderName')
+    fireEvent.change(input, { target: { value: 'fresh' } })
+    fireEvent.keyDown(input, { key: 'Enter' })
+    await waitFor(() => { expect(screen.getByRole('alert').textContent).toBe('level vanished') })
+  })
+
+  it('drops a stale child listing that resolves after a crumb jump', async () => {
     const b = mount()
     await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
-    // The next navigation (into Documents) hangs; a Home-crumb jump supersedes it.
     let resolveSlow!: (value: DirectoryListing) => void
     const slow = new Promise<DirectoryListing>((settle) => { resolveSlow = settle })
     b.listDirectory.mockReturnValueOnce(slow)
     fireEvent.click(screen.getByRole('listitem'))
     fireEvent.click(screen.getByRole('button', { name: 'browser.home' }))
     await waitFor(() => { expect(b.listDirectory).toHaveBeenCalledTimes(3) })
-    await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('Documents') })
-    resolveSlow(listingFor(`${HOME}/Documents`))
+    await waitFor(() => { expect(columns()).toHaveLength(1) })
+    resolveSlow(listingFor(DOCS))
     await new Promise(settle => setTimeout(settle, 0))
-    // The stale Documents listing did not clobber the newer Home level.
-    expect(screen.getByRole('listitem').textContent).toBe('Documents')
+    // The superseded selection preview did not reopen the second pane.
+    expect(columns()).toHaveLength(1)
   })
 
   it('drops a stale failure that rejects after a newer navigation', async () => {
@@ -224,19 +324,82 @@ describe('DirectoryBrowser', () => {
     await waitFor(() => { expect(b.listDirectory).toHaveBeenCalledTimes(3) })
     rejectSlow(new Error('too late to matter'))
     await new Promise(settle => setTimeout(settle, 0))
-    // The superseded failure surfaces no alert over the newer level.
     expect(screen.queryByRole('alert')).toBeNull()
     expect(screen.getByRole('listitem').textContent).toBe('Documents')
   })
 
+  it('drops a stale navigation failure that rejects after a newer jump', async () => {
+    const b = mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(screen.getByRole('listitem'))
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
+    let rejectSlow!: (reason: unknown) => void
+    const slow = new Promise<DirectoryListing>((_settle, fail) => { rejectSlow = fail })
+    b.listDirectory.mockReturnValueOnce(slow)
+    // A slow crumb jump superseded by a second jump.
+    fireEvent.click(screen.getByRole('button', { name: 'browser.home' }))
+    fireEvent.click(screen.getByRole('button', { name: 'Documents' }))
+    await waitFor(() => { expect(b.listDirectory).toHaveBeenCalledTimes(4) })
+    rejectSlow(new Error('late nav failure'))
+    await new Promise(settle => setTimeout(settle, 0))
+    expect(screen.queryByRole('alert')).toBeNull()
+  })
+
+  it('drops a stale navigation listing that resolves after a newer jump', async () => {
+    const b = mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(screen.getByRole('listitem'))
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
+    let resolveSlow!: (value: DirectoryListing) => void
+    const slow = new Promise<DirectoryListing>((settle) => { resolveSlow = settle })
+    b.listDirectory.mockReturnValueOnce(slow)
+    fireEvent.click(screen.getByRole('button', { name: 'browser.home' }))
+    fireEvent.click(screen.getByRole('button', { name: 'Documents' }))
+    await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('harness') })
+    resolveSlow(listingFor(undefined))
+    await new Promise(settle => setTimeout(settle, 0))
+    // The stale home listing did not replace the newer Documents level.
+    expect(screen.getByRole('listitem').textContent).toBe('harness')
+  })
+
+  it('names the create target by its path when the level reports no crumbs', async () => {
+    const bare: DirectoryListing = { path: '/srv/data', home: HOME, crumbs: [], entries: [] }
+    mount({ listDirectory: vi.fn(async () => bare) })
+    await waitFor(() => { expect(screen.getByRole('button', { name: 'browser.newFolder' })).toBeTruthy() })
+    await waitFor(() => {
+      expect(screen.getByRole<HTMLButtonElement>('button', { name: 'browser.newFolder' }).disabled).toBe(false)
+    })
+    fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
+    expect(screen.getByText('browser.createIn:/srv/data')).toBeTruthy()
+  })
+
+  it('refuses to close the nested dialog while the creation is in flight', async () => {
+    const b = mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    let settleCreate!: (path: string) => void
+    b.createDirectory.mockReturnValueOnce(new Promise<string>((settle) => { settleCreate = settle }))
+    fireEvent.click(screen.getByRole('button', { name: 'browser.newFolder' }))
+    const input = screen.getByLabelText('browser.folderName')
+    fireEvent.change(input, { target: { value: 'slow' } })
+    fireEvent.keyDown(input, { key: 'Enter' })
+    // Escape and the mask are both inert while creating.
+    fireEvent.keyDown(screen.getByLabelText('browser.folderName'), { key: 'Escape' })
+    const masks = document.querySelectorAll('[aria-hidden="true"]')
+    fireEvent.click(masks[masks.length - 1]!)
+    expect(screen.getByLabelText('browser.folderName')).toBeTruthy()
+    settleCreate(`${HOME}/slow`)
+    await waitFor(() => { expect(screen.queryByLabelText('browser.folderName')).toBeNull() })
+  })
+
   it('starts back at home on reopen', async () => {
     const b = mount()
     await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
     fireEvent.click(screen.getByRole('listitem'))
-    await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('harness') })
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
     b.view.rerender(<DirectoryBrowser {...b.props} open={false} />)
     b.view.rerender(<DirectoryBrowser {...b.props} open />)
     await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('Documents') })
+    expect(columns()).toHaveLength(1)
     expect(b.listDirectory).toHaveBeenLastCalledWith(undefined)
   })
 })

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

@@ -41,7 +41,7 @@ function pickingShare(): DirectoryPickingInjected {
   return {
     directoryPickerKind: vi.fn(async () => 'dialog' as const),
     pickDirectory: vi.fn(async () => null),
-    listDirectory: vi.fn(async () => ({ path: '/home/u', home: '/home/u', crumbs: [], entries: [] })),
+    listDirectory: vi.fn(async () => ({ path: '/home/u', home: '/home/u', crumbs: [{ name: 'u', path: '/home/u', hidden: false }], entries: [] })),
     createDirectory: vi.fn(async () => '/home/u/new'),
     t: (key: string) => key,
   }
@@ -59,7 +59,7 @@ function mount(
   const share: DirectoryPickingInjected = {
     directoryPickerKind: vi.fn(async () => 'dialog' as const),
     pickDirectory,
-    listDirectory: vi.fn(async () => ({ path: '/home/u', home: '/home/u', crumbs: [], entries: [] })),
+    listDirectory: vi.fn(async () => ({ path: '/home/u', home: '/home/u', crumbs: [{ name: 'u', path: '/home/u', hidden: false }], entries: [] })),
     createDirectory: vi.fn(async () => '/home/u/new'),
     t: key => key,
     ...picking,