fix(ui-workspace): draw Archive session with the archive-box glyph

The session row menu's Archive action carried ic_ds_download_outline_16, a
download tray that reads as "save to disk" rather than "put away". Swap it
for the design's archive glyph — a lidded box with a label slot — added to
the ic_ds_* set as IconArchiveOutline20.

The glyph is native 20, the first of that size in the set, so the menu's
16px icon slot asks for it explicitly. The figma export's 0.11px stroke ring
around the box contour is dropped: it restates the same contour in the same
ink, which currentColor already carries.

packages/client/ui-workspace/src/client/rows/Rows.tsx

@@ -8,7 +8,7 @@
 import { useState } from 'react'
 import clsx from 'clsx'
 import {
-  HoverCard, IconBranchOutline16, IconDownloadOutline16, IconEditOutline16,
+  HoverCard, IconArchiveOutline20, IconBranchOutline16, IconEditOutline16,
   IconEllipsisOutline16, IconFolderClose16, IconFolderOpen16, IconPlusOutline16,
   IconTrashOutline16, IconTriangleRightFill14, Menu, StateDot,
 } from '@deepseek-ai/dsh-client-ui-primitives'
@@ -273,7 +273,8 @@ export function SessionNodeItem({ node, currentId, now, onOpen, onRename, onFork
   const sessionMenuItems = [
     { id: 'rename', label: t('rename'), icon: <IconEditOutline16 /> },
     { id: 'fork', label: t('menu.fork'), icon: <IconBranchOutline16 /> },
-    { id: 'archive', label: t('menu.archiveSession'), icon: <IconDownloadOutline16 /> },
+    // 20-native glyph in the menu's 16px icon slot (Menu.module.css .itemIcon).
+    { id: 'archive', label: t('menu.archiveSession'), icon: <IconArchiveOutline20 size={16} /> },
   ]
   // Figma session cell: pad 8, status slot 16, then a 4px title gap.
   const ownRow = (