Merge latest web transcript base into manual compact

Build-review stack propagation round 1.

packages/host/directory-picker-browse/README.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write packages/host/directory-picker-browse/README.md
-README.md: 23153881b84dcb71dfb05d4f297a5818c410ca77
-README.zh.md: d7010e2941a801ba6358082824330eaae46e42b7
+README.md: 52b5fe7e89f915be3b50324628e9d5c48f1ef94c
+README.zh.md: 742da39470083887a71ddba4a7c8012f0ce0ea1f

packages/host/directory-picker-browse/README.md

@@ -6,7 +6,7 @@ The **in-app browsing backend** of the [directory-picker seam](../directory-pick
 
 Behavior facts: listings return **directories only**, name-sorted, with symlinks-to-directories followed (broken/cyclic links skipped — the probe `stat` failing means "not enterable") and a host-owned `hidden` flag (POSIX dot convention) left for the client to act on; `crumbs` is the root-to-target ancestor chain, the root crumb labeled by its full path (`/`, `C:\`); an absent `list` path means the host account's home directory. `createDirectory` is non-recursive (a missing parent is a real failure, not a level to invent) and validates the name as a single non-blank segment even when called directly, mirroring the wire schema's fence. Both primitives reject an explicit path that is not fully qualified — relative forms, and on Windows the rooted drive-less forms (`\foo`, `/foo`) and incomplete UNC prefixes (`\\`, `\\server`) that `isAbsolute` accepts — with `directory-unreadable`/`directory-create-failed`, instead of letting `resolve` rebase it under the host process cwd or current drive. One `list` call returns at most `maxEntries` rows (config, default 1000 — the bound GitHub's web UI applies to directory listings), and the level streams through a bounded window so memory stays O(maxEntries) no matter how many children the directory holds: a cut level keeps the name-sorted head, counts hidden rows against the bound, probes only windowed candidates, and reports `truncated: true` so the client can say the level is incomplete (a windowed broken symlink is not backfilled from beyond the window — the eviction already marks the level truncated); window insertion is binary with an O(1) full-window tail rejection, and `list` threads the caller's `AbortSignal` so a disconnect or timeout stops the scan instead of letting it outlive the caller. Failures throw the seam's typed `DirectoryPickerError`. Policy rationale: [the directory-picker capability seam Agent Note](../../../.agents/notes/implemented/architecture/2026-07-28-directory-picker-capability-seam.md).
 
-**Dual-face package**: the browser half (`./client`) fills [ui-workspace's](../../client/ui-workspace/README.md) two directory-flow holes with the in-app **Select Workspace Directory** dialog (figma `Harness` 813-23126 family — Miller two-column view whose navigations land selection-anchored: a crumb jump or a submitted path commits the target immediately, then re-selects its actual entry in its parent level once that level arrives — two panes, so stepping back never collapses (a failed or truncated parent leg keeps the single-pane landing; the display root keeps the single wide level); breadcrumb with a click-to-edit path zone whose editor seeds a trailing separator, prefix-filters the listed level from the draft's final segment while typing (case-insensitively, over the listed — possibly truncated — rows only; Enter still navigates by the exact text), and cancels on Escape or when focus leaves the dialog card (window/tab switches and in-card focus moves keep the draft); a fixed-label show-hidden footer toggle over the host's `hidden` flags, with a dot-led typed prefix revealing its matches and the current selection exempt from both filters; nested New-folder dialog), driving `host.listDirectory`/`host.createDirectory` and registering its own locale namespace (`directory-browser`, zh default / en). One cordis.yml row therefore composes both sides of the browse interaction; the client carries no capability-kind branching, and mounting a second flow package fails at load (the holes are `single` kind).
+**Dual-face package**: the browser half (`./client`) fills [ui-workspace's](../../client/ui-workspace/README.md) two directory-flow holes with the in-app **Select Workspace Directory** dialog (figma `Harness` 813-23126 family — Miller two-column view whose navigations land selection-anchored and quiet: the previous view keeps rendering while a crumb jump or a submitted path is scanned (a "Loading…" pill floats over it only once the scan outlives a 300ms silence window, never shifting the columns), then target and parent legs land as one two-pane frame with the target re-selected as its actual parent-level entry — so stepping back never collapses and no intermediate frame flashes (a parent leg outliving its 200ms wait bound lands the target alone and upgrades in place; a failed or truncated parent leg keeps the single-pane landing; the display root keeps the single wide level); breadcrumb with a click-to-edit path zone whose editor seeds a trailing separator, prefix-filters the listed level from the draft's final segment while typing (case-insensitively, over the listed — possibly truncated — rows only; Enter still navigates by the exact text), and cancels on Escape or when focus leaves the dialog card (window/tab switches and in-card focus moves keep the draft); a fixed-label show-hidden footer toggle over the host's `hidden` flags, with a dot-led typed prefix revealing its matches and the current selection exempt from both filters; nested New-folder dialog), driving `host.listDirectory`/`host.createDirectory` and registering its own locale namespace (`directory-browser`, zh default / en). One cordis.yml row therefore composes both sides of the browse interaction; the client carries no capability-kind branching, and mounting a second flow package fails at load (the holes are `single` kind).
 
 ## Model Experience
 

packages/host/directory-picker-browse/README.zh.md

@@ -6,7 +6,7 @@
 
 行为事实：列举**只返回目录**、按名称排序，指向目录的符号链接会被跟随（断链／循环链接被跳过——探测 `stat` 失败即"不可进入"），并携带宿主判定的 `hidden` 标志（POSIX 点前缀约定），展示决策留给客户端；`crumbs` 是从根到目标的祖先链，根 crumb 以完整路径标注（`/`、`C:\`）；`list` 不带路径即列举宿主账户的家目录。`createDirectory` 不递归（父目录缺失是真实失败，不是要补造的层级），且即便被直接调用也把名称校验为单个非空段，与协议 schema 的栅栏一致。两个原语都拒绝非完全限定的显式路径——相对形态，以及 Windows 上 `isAbsolute` 会放行的无盘符有根形态（`\foo`、`/foo`）与不完整的 UNC 前缀（`\\`、`\\server`）——报 `directory-unreadable`／`directory-create-failed`，而不是任由 `resolve` 把它重定位到宿主进程 cwd 或当前盘符之下。单次 `list` 至多返回 `maxEntries` 行（配置项，默认 1000——GitHub 网页端对目录列举采用的同一上限），且层级以流式方式经过一个有界窗口，无论目录有多少子项内存都保持 O(maxEntries)：被截断的层级保留按名排序的头部、隐藏行计入上限、只探测窗口内候选，并报告 `truncated: true`，供客户端提示层级不完整（窗口内的断链符号链接不会从窗口外回填——发生过驱逐本身已把层级标记为截断）；窗口插入为二分查找、满窗尾部单次比较即拒绝，且 `list` 透传调用方的 `AbortSignal`，断连或超时会停止扫描而不是让它在调用方离开后继续。失败抛出 seam 的类型化 `DirectoryPickerError`。策略依据：[目录选择能力 seam Agent Note](../../../.agents/notes/implemented/architecture/2026-07-28-directory-picker-capability-seam.md)。
 
-**双面包**：browser half（`./client`）以应用内 **选择工作区目录** 对话框（figma `Harness` 813-23126 家族——Miller 双列视图，其导航以选中项为锚落地：crumb 跳转或提交的路径会立即提交目标，待父层级到达后再在其中重新选中目标的实际条目——双栏，因此后退绝不塌缩（父层级这一程失败或被截断时保持单栏落地；展示根保持单个宽层级）；带点击即编辑路径区的面包屑，其编辑器预填尾随分隔符、输入时以草稿末段对所列层级做前缀过滤（不区分大小写，且仅作用于已列出、可能被截断的行；Enter 仍按确切文本导航）、按 Escape 或焦点离开对话框卡片即取消（窗口／标签页切换与卡片内焦点移动保留草稿）；基于宿主 `hidden` 标志、标签固定的"显示隐藏"footer 开关，键入以点开头的前缀会显出其匹配项，且当前选中项不受这两种过滤影响；嵌套新建文件夹对话框）填入 [ui-workspace](../../client/ui-workspace/README.md) 的两个目录流洞，驱动 `host.listDirectory`／`host.createDirectory`，并注册自己的 locale 命名空间（`directory-browser`，zh 默认／en）。因此一行 cordis.yml 同时组合浏览交互的两侧；client 侧不含任何能力 kind 分支，挂载第二个流程包会在加载期失败（洞为 `single` kind）。
+**双面包**：browser half（`./client`）以应用内 **选择工作区目录** 对话框（figma `Harness` 813-23126 家族——Miller 双列视图，其导航以选中项为锚、安静落地：扫描 crumb 跳转或提交的路径期间，先前视图持续渲染（"Loading…" 胶囊仅在扫描超出 300ms 静默窗口后才浮于其上，绝不挪动各列），随后目标与父层级两程以单个双栏帧落地，目标被重新选中为其在父层级中的实际条目——因此后退绝不塌缩，也没有中间帧闪现（父层级这一程超出其 200ms 等待上限时，目标单独落地，随后就地升级；父层级这一程失败或被截断时保持单栏落地；展示根保持单个宽层级）；带点击即编辑路径区的面包屑，其编辑器预填尾随分隔符、输入时以草稿末段对所列层级做前缀过滤（不区分大小写，且仅作用于已列出、可能被截断的行；Enter 仍按确切文本导航）、按 Escape 或焦点离开对话框卡片即取消（窗口／标签页切换与卡片内焦点移动保留草稿）；基于宿主 `hidden` 标志、标签固定的"显示隐藏"footer 开关，键入以点开头的前缀会显出其匹配项，且当前选中项不受这两种过滤影响；嵌套新建文件夹对话框）填入 [ui-workspace](../../client/ui-workspace/README.md) 的两个目录流洞，驱动 `host.listDirectory`／`host.createDirectory`，并注册自己的 locale 命名空间（`directory-browser`，zh 默认／en）。因此一行 cordis.yml 同时组合浏览交互的两侧；client 侧不含任何能力 kind 分支，挂载第二个流程包会在加载期失败（洞为 `single` kind）。
 
 ## 模型体验
 

packages/host/directory-picker-browse/src/client/DirectoryBrowser.module.css

@@ -13,6 +13,12 @@
   height: min(500px, calc(100dvh - 32px));
   padding: 0;
   gap: 0;
+  /* The Modal card is an l2 surface and the columns below scroll on it:
+   * rebind the scrollbar indirection to the elevation pair here, on the
+   * surface, so it inherits down to whichever descendant scrolls (the
+   * rebinding contract in ui-theme styles/scrollbar.css). */
+  --dsh-scrollbar-thumb: var(--dsw-alias-scrollbar-bg-l2);
+  --dsh-scrollbar-thumb-hover: var(--dsw-alias-scrollbar-hover-l2);
 }
 
 /* Card-scope wrapper hosting the path editor's Escape and focus-leave
@@ -146,6 +152,8 @@
   flex-direction: column;
   flex: 1 1 0;
   min-height: 0;
+  /* Anchors the floating loading pill (.loadingFloat). */
+  position: relative;
   /* Right inset is slimmer than the left: the trailing column's own 8px
    * scrollbar clearance makes up the optical difference. */
   padding: 16px 16px 16px 24px;
@@ -234,6 +242,10 @@
 .status,
 .error {
   padding: 4px;
+  /* The loading pill occupies the opposite corner while a stale status stays
+   * visible. Reserve its widest localized footprint so wrapped text cannot
+   * run underneath it on a narrow card. */
+  padding-right: 120px;
   font-size: 12px;
   line-height: 18px;
 }
@@ -246,6 +258,23 @@
   color: var(--dsw-alias-state-error-primary);
 }
 
+/* The slow-scan indicator floats over the content's bottom-RIGHT corner on
+ * the card background instead of occupying a row: a scan must never shift
+ * the columns' height, and the stale view keeps rendering beneath it (it
+ * only appears at all once a scan outlives SLOW_SCAN_DELAY_MS). Right,
+ * not left: the truncated/error status rows flow at the bottom LEFT and
+ * stay on screen through a scan, with their reserved right padding keeping
+ * both legible even on a narrow card. After .status in the cascade — the
+ * element carries both classes and this padding must win the
+ * same-specificity race. */
+.loadingFloat {
+  position: absolute;
+  right: 16px;
+  bottom: 8px;
+  padding: 2px 8px;
+  background: var(--dsw-alias-bg-layer-2);
+}
+
 /* Footer: l3 separator on top, symmetric padding so the row sits vertically
  * centered in the bar; New-folder and the show-hidden toggle pin left. */
 .footerBar {

packages/host/directory-picker-browse/src/client/DirectoryBrowser.tsx

@@ -5,10 +5,12 @@
  * breadcrumb, and a click-to-edit path zone; below it a Miller view — one
  * full-width level until a row is selected, then two columns splitting the
  * row evenly (256px floor; level | selected folder's children) around a
- * hairline divider. Navigations land selection-anchored: a crumb jump or a
- * submitted path commits the target immediately, then re-selects it in its
- * parent level once that level arrives, so stepping back keeps two panes
- * away from the display root. Selecting in the
+ * hairline divider. Navigations land selection-anchored and quiet: the
+ * previous view keeps rendering while a crumb jump or a submitted path is
+ * scanned, then target and parent legs land as one two-pane frame (a slow
+ * parent leg falls back to landing the target alone and upgrading in
+ * place), so stepping back keeps two panes away from the display root and
+ * navigation never flashes an intermediate frame. 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
@@ -55,6 +57,24 @@ function failureText(error: unknown): string {
   return error instanceof Error ? error.message : String(error)
 }
 
+/**
+ * How long a scan may stay visually silent before the floating "Loading…"
+ * pill appears. The stale view keeps rendering while a scan is in flight, so
+ * a listing that settles inside this window swaps the panes with no
+ * intermediate frame at all; only a genuinely slow host (a network mount, a
+ * cold disk) surfaces the indicator.
+ */
+const SLOW_SCAN_DELAY_MS = 300
+
+/**
+ * How long a navigation landing waits for its parent leg before committing
+ * the target alone. Inside the window both legs land as ONE two-pane frame —
+ * no single-pane flash between them; past it the target commits single-pane
+ * at once (an Enter-submitted navigation is never held hostage by a stalled
+ * parent) and the late parent leg upgrades the landing in place.
+ */
+const PARENT_LEG_WAIT_MS = 200
+
 /**
  * Breadcrumb rows for display: inside the home subtree the chain starts at a
  * localized Home crumb; outside it the full ancestry shows, the root labeled
@@ -166,6 +186,14 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
   const [selected, setSelected] = useState<DirectoryEntry | null>(null)
   const [child, setChild] = useState<DirectoryListing | null>(null)
   const [loading, setLoading] = useState(false)
+  // Derived from `loading` and `scanWindow` by the slow-scan effect below:
+  // true only once the current listing call has been in flight for
+  // SLOW_SCAN_DELAY_MS, so fast listings never render the indicator at all.
+  const [slowScan, setSlowScan] = useState(false)
+  // Every listing call owns a fresh silence window. `loading` may stay true
+  // across a superseding row pick or across a navigation's target and parent
+  // legs, so its boolean edge cannot identify the start of each scan.
+  const [scanWindow, setScanWindow] = useState(0)
   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)
@@ -209,13 +237,20 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
     return ++requestSeq.current
   }, [])
 
+  /** Hide any prior indicator and start a fresh silence window for one listing call. */
+  const restartSlowScanWindow = useCallback((): void => {
+    setSlowScan(false)
+    setScanWindow(value => value + 1)
+  }, [])
+
   /** Launch one listing under a fresh controller so a later supersession can abort it. */
   const launchListing = useCallback((path: string | undefined): { seq: number; scan: Promise<DirectoryListing> } => {
     const seq = supersede()
     const controller = new AbortController()
     scanController.current = controller
+    restartSlowScanWindow()
     return { seq, scan: listDirectory(path, controller.signal) }
-  }, [supersede, listDirectory])
+  }, [supersede, restartSlowScanWindow, listDirectory])
 
   /**
    * Launch a follow-up listing under the CURRENT supersession seq: a newer
@@ -224,21 +259,25 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
   const continueScan = useCallback((path: string): Promise<DirectoryListing> => {
     const controller = new AbortController()
     scanController.current = controller
+    restartSlowScanWindow()
     return listDirectory(path, controller.signal)
-  }, [listDirectory])
+  }, [restartSlowScanWindow, listDirectory])
 
   /**
-   * Replace the whole view with a freshly navigated level. The target level
-   * commits the moment it arrives (single wide level: the editor closes and
-   * loading ends on this first settlement, so an Enter-submitted navigation
-   * is never withdrawn waiting on anything further). Away from the display
-   * root — the same collapse the crumb header renders, so crumbs and pane
-   * shape never disagree — a parent leg then upgrades the landing in place:
-   * the target's ACTUAL parent-level entry re-selected (left pane = parent,
-   * right pane = the target), so a crumb jump reads as stepping back one
-   * pane. A failed parent leg, or a truncated parent window that lacks the
-   * target, leaves the committed single-pane landing — the upgrade must
-   * never orphan the selection it exists to anchor.
+   * Replace the whole view with a freshly navigated level. Away from the
+   * display root — the same collapse the crumb header renders, so crumbs and
+   * pane shape never disagree — the landing is two-pane: the target's ACTUAL
+   * parent-level entry re-selected (left pane = parent, right pane = the
+   * target), so a crumb jump reads as stepping back one pane. Both legs land
+   * as one frame when the parent leg settles within
+   * {@link PARENT_LEG_WAIT_MS}; past that bound (or at the display root) the
+   * target commits alone — single wide level, the editor closes, loading
+   * ends — and a late parent leg still upgrades the landing in place. A
+   * failed parent leg, or a truncated parent window that lacks the target,
+   * leaves the single-pane landing — the upgrade must never orphan the
+   * selection it exists to anchor. Until whichever commit comes first, the
+   * previous view keeps rendering: navigation swaps the panes, it never
+   * blanks them.
    */
   const navigate = useCallback((path?: string) => {
     const { seq, scan } = launchListing(path)
@@ -246,16 +285,23 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
     setError(null)
     scan.then((target) => {
       if (seq !== requestSeq.current) return
-      setParent(target)
-      setSelected(null)
-      setChild(null)
-      setLoading(false)
-      setPathDraft(null)
+      // The single-pane landing; `landed` makes it first-commit-only, while
+      // the two-pane commit below may still upgrade an already-landed view.
+      let landed = false
+      const landSingle = (): void => {
+        if (landed || seq !== requestSeq.current) return
+        landed = true
+        setParent(target)
+        setSelected(null)
+        setChild(null)
+        setLoading(false)
+        setPathDraft(null)
+      }
       // Arity is label-independent: only the collapsed chain's depth decides.
-      if (displayCrumbs(target, '').length < 2) return
+      if (displayCrumbs(target, '').length < 2) { landSingle(); return }
       const parentCrumb = target.crumbs.at(-2)
       /* v8 ignore next -- narrowing: a two-deep display chain implies a parent crumb (root-to-target inclusive). */
-      if (parentCrumb === undefined) return
+      if (parentCrumb === undefined) { landSingle(); return }
       continueScan(parentCrumb.path).then((parentLevel) => {
         if (seq !== requestSeq.current) return
         // Windows resolves a typed path preserving its case; anchor on the
@@ -263,15 +309,23 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
         const sep = separatorOf(parentLevel)
         const fold = (value: string): string => (sep === '\\' ? value.toLowerCase() : value)
         const match = parentLevel.entries.find(entry => fold(entry.path) === fold(target.path))
-        if (match === undefined) return
+        if (match === undefined) { landSingle(); return }
+        landed = true
         setParent(parentLevel)
         setSelected(match)
         setChild(target)
+        // Idempotent on a late upgrade of a timed-out landing: reopening the
+        // editor or starting a newer scan supersedes this seq, so reaching
+        // here means the draft is closed and the loading flag is this
+        // navigation's own.
+        setLoading(false)
+        setPathDraft(null)
       }, () => {
-        // Swallows the parent-leg failure (its abort included): the
-        // committed single-pane landing stands, and nobody asked to see
-        // the parent level.
+        // The parent-leg failure (its abort included) never surfaces: the
+        // target listed fine, and nobody asked to see the parent level.
+        landSingle()
       })
+      window.setTimeout(landSingle, PARENT_LEG_WAIT_MS)
     }, (reason: unknown) => {
       if (seq !== requestSeq.current) return
       setLoading(false)
@@ -289,7 +343,15 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
   const pathInputRef = useRef<HTMLInputElement | null>(null)
   const editZoneRef = useRef<HTMLButtonElement | null>(null)
 
-  /** Select a row of the listed level and preview its children on the right. */
+  /**
+   * Select a row of the listed level and preview its children on the right.
+   * Deliberately NOT one-frame like navigate(): a pick's first duty is the
+   * immediate selected state on the clicked row, and the pane split IS that
+   * feedback (aria-current pill, crumbs following the selection) — holding
+   * it back for the child listing would make clicks feel dropped. The quiet
+   * rule governs whole-view replacement, where nothing acknowledges the
+   * click but the swap itself.
+   */
   const select = useCallback((entry: DirectoryEntry) => {
     const { seq, scan } = launchListing(entry.path)
     // A pick while the path editor is open adopts the (filtered) row and
@@ -360,6 +422,11 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
       return
     }
     supersede()
+    // Closing mid-scan leaves nothing to load: without this edge the
+    // slow-scan effect keeps arming while hidden and the reopened dialog
+    // would show the indicator on its first frame instead of waiting out a
+    // fresh silence window (reopen's navigate() produces no loading edge).
+    setLoading(false)
     setError(null)
     setPathDraft(null)
     setFolderDraft(null)
@@ -396,6 +463,10 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
       // create target becomes the listed level and the new folder its selection.
       const { seq, scan } = launchListing(targetPath)
       setLoading(true)
+      // Symmetric with navigate/select: a launched scan clears the stale
+      // failure text (and keeps the floating indicator's corner the only
+      // occupant of the content's right edge while it shows).
+      setError(null)
       scan.then((level) => {
         /* v8 ignore next -- same fence as navigate/select; the modal blocks superseding input */
         if (seq !== requestSeq.current) return
@@ -415,6 +486,19 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
     })
   }
 
+  // The slow-scan gate for the loading indicator: each listing call restarts
+  // the timer even when a superseding scan or a navigation's parent leg keeps
+  // `loading` continuously true. A settle inside its own window means the swap
+  // happened with nothing shown.
+  useEffect(() => {
+    if (!loading) {
+      setSlowScan(false)
+      return
+    }
+    const timer = window.setTimeout(() => { setSlowScan(true) }, SLOW_SCAN_DELAY_MS)
+    return () => { window.clearTimeout(timer) }
+  }, [loading, scanWindow])
+
   // After the hooks: a closed dialog renders nothing and evaluates no copy.
   const crumbSource = child ?? parent
   const crumbs = crumbSource === null ? [] : displayCrumbs(crumbSource, t('browser.home'))
@@ -649,11 +733,15 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
               />
             )}
           </div>
-          {loading && <div className={css.status} role="status">{t('browser.loading')}</div>}
+          {loading && slowScan
+          && <div className={clsx(css.status, css.loadingFloat)} role="status">{t('browser.loading')}</div>}
           {/* The backend bounds a level at its complete-result limit; say so
           * whenever a visible pane was cut instead of letting the tail of a
-          * huge directory go silently missing. */}
-          {(parent?.truncated === true || child?.truncated === true) && !loading
+          * huge directory go silently missing. The note describes the panes
+          * on screen, so an in-flight scan leaves it alone — hiding it while
+          * the stale view still shows the cut level would shift the columns
+          * on every navigation away from it. */}
+          {(parent?.truncated === true || child?.truncated === true)
           && <div className={css.status} role="status">{t('browser.truncated')}</div>}
           {error !== null && <div className={css.error} role="alert">{error}</div>}
         </div>

packages/host/directory-picker-browse/tests/directory-browser.spec.tsx

@@ -111,6 +111,12 @@ function rowButton(item: HTMLElement): HTMLButtonElement {
 }
 
 describe('DirectoryBrowser', () => {
+  it('renders nothing and launches no listing while initially closed', () => {
+    const b = mount({ open: false })
+    expect(screen.queryByRole('dialog')).toBeNull()
+    expect(b.listDirectory).not.toHaveBeenCalled()
+  })
+
   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() })
@@ -235,39 +241,249 @@ describe('DirectoryBrowser', () => {
     expect(columns()).toHaveLength(1)
   })
 
-  it('commits the target immediately, aborts a superseded parent leg on the wire, and drops its late resolution', async () => {
-    const signals: (AbortSignal | undefined)[] = []
-    const settlers: ((value: DirectoryListing) => void)[] = []
-    // Only the FIRST explicit HOME request (the parent leg) hangs; the later
-    // home crumb jump lists normally.
-    let homeCalls = 0
-    const listDirectory = vi.fn(async (path?: string, signal?: AbortSignal) => {
-      signals.push(signal)
-      if (path === HOME && ++homeCalls === 1) {
-        return new Promise<DirectoryListing>((resolve) => { settlers.push(resolve) })
-      }
-      return listingFor(path)
+  it('lands the target single-pane at the wait bound, aborts a superseded parent leg on the wire, and drops its late resolution', async () => {
+    vi.useFakeTimers()
+    try {
+      const signals: (AbortSignal | undefined)[] = []
+      const settlers: ((value: DirectoryListing) => void)[] = []
+      // Only the FIRST explicit HOME request (the parent leg) hangs; the
+      // later home crumb jump lists normally.
+      let homeCalls = 0
+      const listDirectory = vi.fn((path?: string, signal?: AbortSignal) => {
+        signals.push(signal)
+        if (path === HOME && ++homeCalls === 1) {
+          return new Promise<DirectoryListing>((resolve) => { settlers.push(resolve) })
+        }
+        return Promise.resolve(listingFor(path))
+      })
+      mount({ listDirectory })
+      await act(async () => {})
+      fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
+      fireEvent.change(screen.getByLabelText<HTMLInputElement>('browser.editPath'), { target: { value: DOCS } })
+      fireEvent.keyDown(screen.getByLabelText('browser.editPath'), { key: 'Enter' })
+      // The target settled but the parent leg hangs: inside the wait bound
+      // nothing commits yet.
+      await act(async () => {})
+      expect(settlers).toHaveLength(1)
+      expect(screen.getByLabelText('browser.editPath', { selector: 'input' })).toBeTruthy()
+      // The wait bound expires: the target commits alone — editor closed,
+      // single-pane DOCS level.
+      await act(async () => { vi.advanceTimersByTime(200) })
+      expect(screen.getByRole('listitem').textContent).toBe('harness')
+      expect(screen.queryByLabelText('browser.editPath', { selector: 'input' })).toBeNull()
+      expect(columns()).toHaveLength(1)
+      // A newer jump aborts the pending parent leg ON THE WIRE, not merely
+      // dropping its settlement.
+      fireEvent.click(screen.getByRole('button', { name: 'browser.home' }))
+      expect(signals[2]?.aborted).toBe(true)
+      await act(async () => {})
+      expect(screen.getByRole('listitem').textContent).toBe('Documents')
+      // Its late resolution changes nothing either.
+      await act(async () => { settlers[0]!(listingFor(HOME)) })
+      expect(columns()).toHaveLength(1)
+      expect(rowButton(screen.getByRole('listitem')).getAttribute('aria-current')).toBeNull()
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  /**
+   * Listing fake whose explicit-path scans stay pending until the test
+   * settles them by path; the absent-path form (the initial home listing)
+   * resolves normally so mounting is a one-flush setup.
+   */
+  function manualLister() {
+    const settlers = new Map<string, (value: DirectoryListing) => void>()
+    const listDirectory = vi.fn((path?: string, _signal?: AbortSignal) => {
+      if (path === undefined) return Promise.resolve(listingFor(path))
+      return new Promise<DirectoryListing>((resolve) => { settlers.set(path, resolve) })
     })
-    mount({ listDirectory })
-    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
-    fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
-    fireEvent.change(screen.getByLabelText<HTMLInputElement>('browser.editPath'), { target: { value: DOCS } })
-    fireEvent.keyDown(screen.getByLabelText('browser.editPath'), { key: 'Enter' })
-    // The target leg commits at once: editor closed, single-pane DOCS level,
-    // while the parent leg (upgrade) is still in flight.
-    await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('harness') })
-    expect(screen.queryByLabelText('browser.editPath', { selector: 'input' })).toBeNull()
-    expect(columns()).toHaveLength(1)
-    await waitFor(() => { expect(settlers).toHaveLength(1) })
-    // A newer jump aborts the pending parent leg ON THE WIRE, not merely
-    // dropping its settlement.
-    fireEvent.click(screen.getByRole('button', { name: 'browser.home' }))
-    expect(signals[2]?.aborted).toBe(true)
-    await waitFor(() => { expect(screen.getByRole('listitem').textContent).toBe('Documents') })
-    // Its late resolution changes nothing either.
-    await act(async () => { settlers[0]!(listingFor(HOME)) })
-    expect(columns()).toHaveLength(1)
-    expect(rowButton(screen.getByRole('listitem')).getAttribute('aria-current')).toBeNull()
+    return { settlers, listDirectory }
+  }
+
+  it('lands a navigation as ONE two-pane frame: the stale view holds until both legs arrive', async () => {
+    vi.useFakeTimers()
+    try {
+      const { settlers, listDirectory } = manualLister()
+      mount({ listDirectory })
+      await act(async () => {})
+      fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
+      fireEvent.change(screen.getByLabelText<HTMLInputElement>('browser.editPath'), { target: { value: DOCS } })
+      fireEvent.keyDown(screen.getByLabelText('browser.editPath'), { key: 'Enter' })
+      // The target settles while the parent leg is still in flight: nothing
+      // commits yet — the editor stays open over the stale home level, and no
+      // single-pane DOCS frame ever renders.
+      await act(async () => { settlers.get(DOCS)!(listingFor(DOCS)) })
+      expect(screen.getByLabelText('browser.editPath', { selector: 'input' })).toBeTruthy()
+      expect(screen.queryByText('harness')).toBeNull()
+      // The parent leg settles inside the wait bound: one commit straight to
+      // the two-pane landing, editor closed.
+      await act(async () => { settlers.get(HOME)!(listingFor(HOME)) })
+      expect(columns()).toHaveLength(2)
+      expect(rowButton(within(columns()[0]!).getByRole('listitem')).getAttribute('aria-current')).toBe('true')
+      expect(within(columns()[0]!).getByText('Documents')).toBeTruthy()
+      expect(within(columns()[1]!).getByText('harness')).toBeTruthy()
+      expect(screen.queryByLabelText('browser.editPath', { selector: 'input' })).toBeNull()
+      // The wait-bound timer firing after the landing is a no-op.
+      await act(async () => { vi.advanceTimersByTime(200) })
+      expect(columns()).toHaveLength(2)
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('a stalled parent leg lands the target alone at the wait bound, then upgrades in place', async () => {
+    vi.useFakeTimers()
+    try {
+      const { settlers, listDirectory } = manualLister()
+      mount({ listDirectory })
+      await act(async () => {})
+      fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
+      fireEvent.change(screen.getByLabelText<HTMLInputElement>('browser.editPath'), { target: { value: DOCS } })
+      fireEvent.keyDown(screen.getByLabelText('browser.editPath'), { key: 'Enter' })
+      // The target can consume most of the outer scan's silence window.
+      await act(async () => { vi.advanceTimersByTime(250) })
+      await act(async () => { settlers.get(DOCS)!(listingFor(DOCS)) })
+      // Its parent leg gets a fresh silence window. Crossing the original
+      // scan's 300ms deadline therefore cannot flash the indicator during the
+      // bounded landing wait.
+      await act(async () => { vi.advanceTimersByTime(199) })
+      expect(screen.queryByText('browser.loading')).toBeNull()
+      // The parent leg outlives PARENT_LEG_WAIT_MS: the target lands alone.
+      await act(async () => { vi.advanceTimersByTime(1) })
+      expect(columns()).toHaveLength(1)
+      expect(screen.getByRole('listitem').textContent).toBe('harness')
+      expect(screen.queryByLabelText('browser.editPath', { selector: 'input' })).toBeNull()
+      // The late parent leg still upgrades the landing in place, exactly as
+      // if it had made the bound. (Reopening the editor meanwhile would
+      // supersede the upgrade — the editor-open handler withdraws pending
+      // listings — so a late upgrade can never close a resumed draft.)
+      await act(async () => { settlers.get(HOME)!(listingFor(HOME)) })
+      expect(columns()).toHaveLength(2)
+      expect(rowButton(within(columns()[0]!).getByRole('listitem')).getAttribute('aria-current')).toBe('true')
+      expect(within(columns()[1]!).getByText('harness')).toBeTruthy()
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('Escape inside the landing window withdraws the submitted navigation', async () => {
+    vi.useFakeTimers()
+    try {
+      const { settlers, listDirectory } = manualLister()
+      mount({ listDirectory })
+      await act(async () => {})
+      fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
+      const input = screen.getByLabelText<HTMLInputElement>('browser.editPath')
+      fireEvent.change(input, { target: { value: DOCS } })
+      fireEvent.keyDown(input, { key: 'Enter' })
+      await act(async () => { settlers.get(DOCS)!(listingFor(DOCS)) })
+      // Nothing has committed yet; Escape supersedes the landing entirely.
+      fireEvent.keyDown(input, { key: 'Escape' })
+      await act(async () => { vi.advanceTimersByTime(200) })
+      expect(columns()).toHaveLength(1)
+      expect(screen.queryByText('harness')).toBeNull()
+      expect(within(columns()[0]!).getByText('Documents')).toBeTruthy()
+      expect(screen.queryByLabelText('browser.editPath', { selector: 'input' })).toBeNull()
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('shows the loading indicator only once a scan outlives its silence window, floating over the stale view', async () => {
+    vi.useFakeTimers()
+    try {
+      // The home level is truncated so its note is on screen when the slow
+      // scan starts: dropping the note's old !loading guard means it must
+      // keep rendering through the scan, coexisting with the indicator.
+      const settlers = new Map<string, (value: DirectoryListing) => void>()
+      const listDirectory = vi.fn((path?: string, _signal?: AbortSignal) => {
+        if (path === undefined) return Promise.resolve({ ...listingFor(path), truncated: true })
+        return new Promise<DirectoryListing>((resolve) => { settlers.set(path, resolve) })
+      })
+      mount({ listDirectory })
+      await act(async () => {})
+      expect(screen.queryByText('browser.loading')).toBeNull()
+      expect(screen.getByText('browser.truncated')).toBeTruthy()
+      fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
+      fireEvent.change(screen.getByLabelText<HTMLInputElement>('browser.editPath'), { target: { value: DOCS } })
+      fireEvent.keyDown(screen.getByLabelText('browser.editPath'), { key: 'Enter' })
+      // In flight but still inside the silence window: no indicator, and the
+      // stale level's truncated note stays put (no layout churn on launch).
+      expect(screen.queryByText('browser.loading')).toBeNull()
+      expect(screen.getByText('browser.truncated')).toBeTruthy()
+      await act(async () => { vi.advanceTimersByTime(300) })
+      // Past it: the indicator floats while the stale level — truncated note
+      // included — keeps rendering beneath it.
+      expect(screen.getByText('browser.loading')).toBeTruthy()
+      expect(screen.getByText('browser.truncated')).toBeTruthy()
+      expect(screen.getByText('Documents')).toBeTruthy()
+      // Landing (both legs) retires the indicator with the scan, and the
+      // fresh listings' own truncated state replaces the stale note.
+      await act(async () => { settlers.get(DOCS)!(listingFor(DOCS)) })
+      await act(async () => { settlers.get(HOME)!(listingFor(HOME)) })
+      expect(screen.queryByText('browser.loading')).toBeNull()
+      expect(screen.queryByText('browser.truncated')).toBeNull()
+      expect(columns()).toHaveLength(2)
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('restarts the silence window when a row pick supersedes a pending scan', async () => {
+    vi.useFakeTimers()
+    try {
+      const pending: ((value: DirectoryListing) => void)[] = []
+      const listDirectory = vi.fn((path?: string, _signal?: AbortSignal) => {
+        if (path === undefined) return Promise.resolve(listingFor(path))
+        return new Promise<DirectoryListing>((resolve) => { pending.push(resolve) })
+      })
+      mount({ listDirectory })
+      await act(async () => {})
+      const documents = rowButton(screen.getByRole('listitem'))
+      fireEvent.click(documents)
+      await act(async () => { vi.advanceTimersByTime(300) })
+      expect(screen.getByText('browser.loading')).toBeTruthy()
+      // The same row remains actionable while its preview is pending. A second
+      // pick starts a new listing without a false `loading` edge.
+      fireEvent.click(documents)
+      expect(screen.queryByText('browser.loading')).toBeNull()
+      await act(async () => { vi.advanceTimersByTime(299) })
+      expect(screen.queryByText('browser.loading')).toBeNull()
+      await act(async () => { vi.advanceTimersByTime(1) })
+      expect(screen.getByText('browser.loading')).toBeTruthy()
+      await act(async () => { pending.at(-1)!(listingFor(DOCS)) })
+    } finally {
+      vi.useRealTimers()
+    }
+  })
+
+  it('a close mid-scan resets the slow-scan gate: reopening waits a fresh silence window', async () => {
+    vi.useFakeTimers()
+    try {
+      // Every home listing hangs: the initial open's scan is the one the
+      // close interrupts, and the reopen's scan proves the fresh window.
+      const settlers: ((value: DirectoryListing) => void)[] = []
+      const listDirectory = vi.fn((_path?: string, _signal?: AbortSignal) =>
+        new Promise<DirectoryListing>((resolve) => { settlers.push(resolve) }))
+      const { view, props } = mount({ listDirectory })
+      await act(async () => { vi.advanceTimersByTime(300) })
+      expect(screen.getByText('browser.loading')).toBeTruthy()
+      // Close while the scan is in flight, then reopen: the first frame must
+      // wait out a fresh silence window, not inherit the armed indicator.
+      view.rerender(<DirectoryBrowser {...props} open={false} />)
+      view.rerender(<DirectoryBrowser {...props} open />)
+      await act(async () => {})
+      expect(screen.queryByText('browser.loading')).toBeNull()
+      await act(async () => { vi.advanceTimersByTime(300) })
+      expect(screen.getByText('browser.loading')).toBeTruthy()
+      // The reopened scan settles normally.
+      await act(async () => { settlers.at(-1)!(listingFor(undefined)) })
+      expect(screen.queryByText('browser.loading')).toBeNull()
+      expect(screen.getByText('Documents')).toBeTruthy()
+    } finally {
+      vi.useRealTimers()
+    }
   })
 
   it('keeps the single-pane landing when the truncated parent level lacks the target', async () => {