fix(assistant): the window's menu and trip list keep the keyboard in reach

The home chat's trip list opened before its trips had loaded, so the focus
stayed on its button and no trip could be reached by keyboard; the first trip
now takes the focus once the list is there. The header's menu says whether it
is open, and closed by Escape or a pick it hands the focus back to its
button, so the next Escape closes the window again. The open chat in the
history list is announced as the current one.

client/src/components/Packing/PackingPopover.test.tsx

@@ -1,4 +1,4 @@
-// FE-PACKPOP-001 to FE-PACKPOP-008
+// FE-PACKPOP-001 to FE-PACKPOP-009
 import { describe, it, expect, vi } from 'vitest'
 import { useRef } from 'react'
 import { render, screen, fireEvent } from '../../../tests/helpers/render'
@@ -56,6 +56,15 @@ describe('PopoverItem', () => {
     expect(danger.style.background).toBe('none')
   })
 
+  it('FE-PACKPOP-009: the entry open now is said to be the current one, not only tinted', () => {
+    render(<>
+      <PopoverItem icon={null} label="Temples" active current onClick={() => {}} />
+      <PopoverItem icon={null} label="Food" onClick={() => {}} />
+    </>)
+    expect(screen.getByRole('button', { name: 'Temples' })).toHaveAttribute('aria-current', 'true')
+    expect(screen.getByRole('button', { name: 'Food' })).not.toHaveAttribute('aria-current')
+  })
+
   it('FE-PACKPOP-004: the composer button fades while there is nothing to add', () => {
     expect(composerConfirm(false)).toMatchObject({ opacity: 0.35, cursor: 'default' })
     expect(composerConfirm(true)).toMatchObject({ opacity: 1, cursor: 'pointer' })

client/src/components/Packing/PackingPopover.tsx

@@ -7,6 +7,8 @@ interface PopoverItemProps {
   label: string
   onClick: () => void
   active?: boolean
+  /** The entry is the one open now (a chat in a history list), said so to a screen reader too. */
+  current?: boolean
   danger?: boolean
   /** A secondary line, such as Add bag, in the faint text colour. */
   muted?: boolean
@@ -14,11 +16,12 @@ interface PopoverItemProps {
   trailing?: ReactNode
 }
 
-export function PopoverItem({ icon, label, onClick, active = false, danger = false, muted = false, trailing }: PopoverItemProps) {
+export function PopoverItem({ icon, label, onClick, active = false, current = false, danger = false, muted = false, trailing }: PopoverItemProps) {
   const tone = danger ? '#ef4444' : muted ? 'var(--text-faint)' : 'var(--text-primary)'
   return (
     <button type="button"
       onClick={onClick}
+      aria-current={current || undefined}
       style={{
         display: 'flex', alignItems: 'center', gap: 9, width: '100%',
         padding: '8px 10px', borderRadius: 9, border: 'none', cursor: 'pointer',