test(web): adapt workspace browser e2e interactions to the compact sidebar

The sidebar redesign removed group session counts, collapsed search into a
header action, and moved grouping into the View options menu. Update the
browser scenarios that waited on the old surfaces:

- Wait on the Ungrouped bucket row instead of the removed session-count text.
- Expand the collapsed search control before filling the renamed input.
- Open the View options menu instead of the removed Group by button.
- Assert the persisted grouping under the new dsh.workspace.view.v4 key.
- built-boot: assert the fixture workspace group row instead of its count.

apps/web/tests/built-boot.snapshot.ts

@@ -21,7 +21,12 @@ it('boots the built plugin graph and renders a fixture session end to end', asyn
 
   // The sidebar renders from the boot graph: every inject layer activated.
   const tree = await screen.findByRole('tree', { name: 'Sessions' }, { timeout: 10_000 })
-  await within(tree).findByText('4 sessions')
+  // The compact layout dropped group session counts; the fixture workspace
+  // group row renders immediately with its sessions beneath it.
+  const fixtureGroup = (await within(tree).findAllByText('fixture'))
+    .map(el => el.closest<HTMLElement>('[role="treeitem"]'))
+    .find(el => el?.getAttribute('aria-expanded') !== null)
+  if (fixtureGroup === undefined) throw new Error('fixture Workspace group missing')
 
   // The resident fixture has both a question and an approval; composer routing
   // exposes the question first, and the assembled workspace plugin mirrors that