fix(host): review round 4 — post-commit refocus covers right-pane picks; combobox semantics recorded as deferred

.agents/notes/implemented/architecture/2026-07-28-directory-picker-capability-seam.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 .agents/notes/implemented/architecture/2026-07-28-directory-picker-capability-seam.md
-2026-07-28-directory-picker-capability-seam.md: f633cd60b32c10e63814bf06a06773d2dba396f2
-2026-07-28-directory-picker-capability-seam.zh.md: b708e6fffa46cf51fd35154bfc2b947d955e5e9c
+2026-07-28-directory-picker-capability-seam.md: 550d51cf2e4e5b70b0844401d42bfea2342612e7
+2026-07-28-directory-picker-capability-seam.zh.md: afaf277e866349b20d370fe1fd638b0c71e1a3e7

.agents/notes/implemented/architecture/2026-07-28-directory-picker-capability-seam.md

@@ -19,7 +19,7 @@ Placement and policy rulings folded into this decision:
 - **Not the `ctx.fs` seam.** `packages/fs/` is the model/session-facing storage stack (policy events, sandbox-swappable backends). Riding it would couple GUI browsing to the model's confinement backend — swapping `fs-sandbox` for the model must never change GUI behavior — and OS facts (home anchoring, hidden conventions) are not storage primitives. The picker seam stays presentation-free and model-free; `packages/host/` is its consumer-domain home.
 - **Dependency survey (hand-roll vs adopt).** Node's stdlib *is* the maintained cross-platform OS layer (`readdir(withFileTypes)`, `homedir`, path semantics); surveyed alternatives fail the dependency bar — file-manager packages (`node-file-manager`, `files-and-folders`, Syncfusion's provider) are whole HTTP apps (fit), drive-letter helpers (`drivelist` native addon, `windows-drive-letters` ~7y stale) fail health/proportionality. The browse backend is a thin adapter over stdlib.
 - **Hidden entries: return-and-flag.** The host stamps `hidden` (POSIX dot convention) and returns everything; the client filters. Display policy stays client-side, and the show-hidden toggle shipped as exactly that client-only change: a fixed-label footer toggle whose state lives in the pressed presentation (`aria-pressed` + check glyph), a dot-led path-draft prefix reveals the hidden entries it names, and the current selection is exempt from both the hidden and the prefix filter (it anchors the two-pane view). Windows' `FILE_ATTRIBUTE_HIDDEN` is not exposed by dirents — documented limitation until a native probe pays for itself.
-- **Path-editor cancel scope: the dialog card.** The browse client's path editor cancels on Escape and on focus leaving the card, both observed at a card-scope wrapper rather than the input — after Tab parks focus on a filtered row the input is off the event path, yet Escape must collapse the editor (not the dialog) and a later focus departure must still cancel. Non-cancel exemptions: window/tab focus loss, in-card focus moves, and pointer paths (rows and the toggle suppress focus steal on mousedown while editing). Separators for seeding and draft-tail filtering are inferred from `listing.home`; the wire-field alternative below records the deferred authoritative form.
+- **Path-editor cancel scope: the dialog card.** The browse client's path editor cancels on Escape and on focus leaving the card, both observed at a card-scope wrapper rather than the input — after Tab parks focus on a filtered row the input is off the event path, yet Escape must collapse the editor (not the dialog) and a later focus departure must still cancel. Non-cancel exemptions: window/tab focus loss, in-card focus moves, and pointer paths (rows and the toggle suppress focus steal on mousedown while editing). Separators for seeding and draft-tail filtering are inferred from `listing.home`; the wire-field alternative below records the deferred authoritative form. Combobox semantics between the editor and the list it filters (`aria-expanded`/`aria-controls`/active-descendant, result announcements) are likewise deferred — today they read to assistive tech as separate widgets.
 - **Symlinks: follow for enterability.** `stat` probes symlinks (broken/cyclic → skipped); crumbs keep the logical path the operator navigated, and `workspace.create` already canonicalizes via realpath at adoption.
 - **Listing levels are bounded, and streamed.** One `list` call returns at most `maxEntries` rows (config, default 1000 — GitHub's web-UI directory-listing bound). The level streams via `opendir` into a name-sorted window of `maxEntries + 1` candidates, so memory stays O(maxEntries) and enterability probing touches only windowed candidates; the wire `DirectoryListing` carries a required `truncated` flag so the client states incompleteness instead of silently missing tail entries. 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 (an oversized level must not pay a window scan per dirent), and `list(path, signal)` threads the carrier's request signal so a scan of a stalled network directory cannot outlive a disconnected caller — every await in the scan (open, each read, each symlink probe) races the signal, an aborted exit abandons rather than awaits the close (Node queues close behind in-flight reads), and abandoned settlements are swallowed so cleanup can never surface as an unhandled rejection. An unbounded level is a memory/responsiveness hole for large or adversarial directories.
 - **Whole-filesystem scope, no roots config.** `workspace.create` accepts arbitrary paths and the API serves bash-driving methods, so a browse root would be UX scoping, not a boundary; configurability without a consumer fails the evidence bar. Deferred until a deployment needs it.

.agents/notes/implemented/architecture/2026-07-28-directory-picker-capability-seam.zh.md

@@ -19,7 +19,7 @@ web GUI 的"打开本地文件夹"流程被焊死在一种交互上：`host.pick
 - **不用 `ctx.fs` seam。** `packages/fs/` 是面向模型／会话的存储栈（policy 事件、sandbox 可换后端）。骑上去会把 GUI 浏览耦合进模型的限制后端——为模型换 `fs-sandbox` 绝不能改变 GUI 行为——而 OS 事实（home 锚定、隐藏约定）也不是存储原语。picker seam 保持无展示、无模型；`packages/host/` 是它消费方域的家。
 - **依赖调研（手写 vs 引入）。** Node 标准库本身就是维护中的跨平台 OS 层（`readdir(withFileTypes)`、`homedir`、路径语义）；调研过的替代品都过不了依赖门槛——文件管理器包（`node-file-manager`、`files-and-folders`、Syncfusion 的 provider）是整套 HTTP 应用（契合度不过），盘符工具（原生插件 `drivelist`、约七年未更的 `windows-drive-letters`）健康度／比例失当。browse 后端是标准库上的薄适配。
 - **隐藏条目：返回并打标。** 宿主标注 `hidden`（POSIX 点前缀约定）并返回全部条目；客户端过滤。展示策略留在客户端，"显示隐藏"开关正是作为这一纯客户端改动落地：标签固定的 footer 开关，其状态由按下态呈现承载（`aria-pressed` + 勾选符号）；以点开头的路径草稿前缀会显出它所指名的隐藏条目；当前选中项则不受隐藏与前缀两种过滤影响（它锚定着双栏视图）。Windows 的 `FILE_ATTRIBUTE_HIDDEN` 不被 dirent 暴露——记为限制，直到原生探测值回其成本。
-- **路径编辑器的取消范围：对话框卡片。** browse 客户端的路径编辑器在按 Escape 与焦点离开卡片时取消，两者都在卡片范围的包装层而非输入框上监听——Tab 把焦点停到某个过滤命中的行之后，输入框已不在事件路径上，但 Escape 仍须收起编辑器（而非对话框），其后的焦点离开也仍须取消。不取消的豁免：窗口／标签页失焦、卡片内焦点移动，以及指针路径（编辑期间行与开关在 mousedown 时抑制焦点夺取）。预填与草稿末段过滤所用的分隔符从 `listing.home` 推断；下文的线上字段替代方案记录了被延期的权威形态。
+- **路径编辑器的取消范围：对话框卡片。** browse 客户端的路径编辑器在按 Escape 与焦点离开卡片时取消，两者都在卡片范围的包装层而非输入框上监听——Tab 把焦点停到某个过滤命中的行之后，输入框已不在事件路径上，但 Escape 仍须收起编辑器（而非对话框），其后的焦点离开也仍须取消。不取消的豁免：窗口／标签页失焦、卡片内焦点移动，以及指针路径（编辑期间行与开关在 mousedown 时抑制焦点夺取）。预填与草稿末段过滤所用的分隔符从 `listing.home` 推断；下文的线上字段替代方案记录了被延期的权威形态。编辑器与其过滤的列表之间的 combobox 语义（`aria-expanded`／`aria-controls`／active-descendant、结果播报）同样被延期——目前二者在辅助技术看来是彼此独立的控件。
 - **符号链接：为可进入性而跟随。** 用 `stat` 探测符号链接（断链／循环→跳过）；面包屑保留操作者导航的逻辑路径，`workspace.create` 在接纳时本就做 realpath 规范化。
 - **列举层级有上限，且流式处理。** 单次 `list` 至多返回 `maxEntries` 行（配置项，默认 1000——GitHub 网页端目录列举的同一上限）。层级经 `opendir` 流入一个按名排序、容量 `maxEntries + 1` 的候选窗口，内存保持 O(maxEntries)，可进入性探测只触及窗口内候选；线上 `DirectoryListing` 携带必填的 `truncated` 标志，让客户端明示不完整而不是静默缺尾。窗口内的断链符号链接不从窗口外回填——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（超大层级不能为每个 dirent 付出一次全窗扫描），且 `list(path, signal)` 透传载体的请求信号，滞塞网络目录的扫描不会在调用方断连后继续存活——扫描中的每个 await（打开、每次读取、每次符号链接探测）都与信号赛跑，中止路径放弃而非等待 close（Node 会把 close 排在在飞读取之后），被放弃的 settlement 全部吞掉，清理不会以未处理拒绝的形式冒出。无上限的层级对超大或恶意构造的目录就是内存／响应性漏洞。
 - **全盘可浏览，不做 roots 配置。** `workspace.create` 接受任意路径且 API 本就提供驱动 bash 的方法，浏览根只会是 UX 范围而非边界；没有消费方的可配置性过不了证据门槛。等到有部署需要再做。

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

@@ -15,6 +15,13 @@
   gap: 0;
 }
 
+/* Card-scope wrapper hosting the path editor's Escape and focus-leave
+ * observers; display:contents keeps header/content/footer as direct flex
+ * children of the Modal card. */
+.editorScope {
+  display: contents;
+}
+
 /* Header block: pl24 pr14 pt16 pb8, 8px between title row and crumb row. */
 .header {
   display: flex;
@@ -284,13 +291,6 @@
   color: var(--dsw-alias-label-primary);
 }
 
-/* Card-scope wrapper hosting the path editor's Escape and focus-leave
- * observers; display:contents keeps header/content/footer as direct flex
- * children of the Modal card. */
-.editorScope {
-  display: contents;
-}
-
 .footerGap {
   flex: 1 1 0;
 }

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

@@ -132,13 +132,11 @@ function LevelColumn({ entries, selectedPath, busy, onPick, showHidden, filterPr
               // where the blur lands before our guards) drop this click.
               // Outside editing, rows keep native focus behavior.
               onMouseDown={pathEditing ? (event) => { event.preventDefault() } : undefined}
-              onClick={(event) => {
-                // A pick during editing is about to unmount the focused
-                // input; park focus on the picked row so keyboard traversal
-                // stays inside the dialog (the Modal has no focus trap).
-                if (pathEditing) event.currentTarget.focus()
-                onPick(entry)
-              }}
+              // Editing-time focus parking happens after commit (the
+              // DirectoryBrowser refocus effect): a right-pane pick replaces
+              // this very column, so focusing the clicked node here would
+              // still fall to body.
+              onClick={() => { onPick(entry) }}
             >
               {selected
                 ? <IconFolderOpen16 size={16} className={css.rowIconSelected} />
@@ -235,11 +233,18 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
     })
   }, [launchListing])
 
+  // An editing-time pick parks focus on the selection after commit; the
+  // flag is set by select() and consumed by the refocus effect below the
+  // miller-row ref.
+  const refocusPick = useRef(false)
+
   /** Select a row of the listed level and preview its children on the right. */
   const select = useCallback((entry: DirectoryEntry) => {
     const { seq, scan } = launchListing(entry.path)
     // A pick while the path editor is open adopts the (filtered) row and
-    // closes the editor — the draft served its purpose.
+    // closes the editor — the draft served its purpose. Focus re-parks on
+    // the selection after commit (see the refocus effect below).
+    if (pathDraft !== null) refocusPick.current = true
     setPathDraft(null)
     setSelected(entry)
     setChild(null)
@@ -257,7 +262,7 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
       // breadcrumb still names the level: fall back to the single pane.
       setSelected(null)
     })
-  }, [launchListing])
+  }, [launchListing, pathDraft])
 
   /** Abandon path editing (Escape or clicking away) and restore the crumb view. */
   const cancelPathEdit = useCallback(() => {
@@ -368,6 +373,18 @@ export function DirectoryBrowser({ open, listDirectory, createDirectory, onOpen,
     const row = millerRowRef.current
     if (row !== null && childPath !== undefined) row.scrollLeft = row.scrollWidth
   }, [childPath])
+  // An editing-time pick unmounts the focused input, and a right-pane pick
+  // additionally replaces the picked button's whole column (advance swaps
+  // both panes): park focus on the selection's row — aria-current in the
+  // freshly rendered left pane — after commit, so keyboard traversal stays
+  // inside the dialog (the Modal has no focus trap).
+  useEffect(() => {
+    if (!refocusPick.current) return
+    refocusPick.current = false
+    /* v8 ignore next 2 -- narrowing guard: the pick that set the flag just rendered its aria-current row inside the miller row. */
+    const row = millerRowRef.current?.querySelector<HTMLButtonElement>('button[aria-current="true"]')
+    row?.focus()
+  })
 
   if (!open) return null
   const twoPane = selected !== null

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

@@ -369,6 +369,25 @@ describe('DirectoryBrowser', () => {
     expect(screen.getByRole('button', { name: 'browser.home' })).toBeTruthy()
   })
 
+  it('a right-pane pick while editing parks focus on the advanced selection', async () => {
+    mount()
+    await waitFor(() => { expect(screen.getByRole('listitem')).toBeTruthy() })
+    fireEvent.click(rowButton(screen.getByRole('listitem')))
+    await waitFor(() => { expect(columns()).toHaveLength(2) })
+    fireEvent.click(screen.getByRole('button', { name: 'browser.editPath' }))
+    const input = screen.getByLabelText<HTMLInputElement>('browser.editPath')
+    fireEvent.change(input, { target: { value: `${DOCS}/h` } })
+    // The advance replaces BOTH panes (the picked button's own column
+    // unmounts), so focus is re-parked on the selection's aria-current row
+    // in the freshly rendered left pane rather than the clicked node.
+    const row = rowButton(within(columns()[1]!).getByRole('listitem'))
+    fireEvent.mouseDown(row)
+    fireEvent.click(row)
+    expect(screen.queryByLabelText('browser.editPath', { selector: 'input' })).toBeNull()
+    await waitFor(() => { expect(document.activeElement?.textContent).toBe('harness') })
+    expect(document.activeElement?.getAttribute('aria-current')).toBe('true')
+  })
+
   it('seeds and filters with backslashes on a Windows-rooted listing', async () => {
     const ROOT = 'C:\\'
     const windowsListing: DirectoryListing = {