test(gui): settings package suites; ledger-judged re-registration

Full per-file coverage for the three settings packages: invariant
companions, store mirroring with revision guards, behavior-shaped
section/shell specs (props-fed, real store engine), and apply-level
suites on a real Context + SlotCore covering declaration-aware deferral
and HMR collapse recovery. All three registrants now judge presence on
the slot ledger instead of a local disposer, which went stale when a
parent redeclaration cascade removed the entry (ds-review-bot finding);
the locale re-register path keeps the same idempotence.

packages/client/ui-settings/tests/settings-root.spec.tsx

@@ -0,0 +1,155 @@
+// @vitest-environment jsdom
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import { act, cleanup, fireEvent, render, screen } from '@testing-library/react'
+import type { SettingsRootComponentProps } from '../src/client/contract/slots.ts'
+import { SettingsRoot } from '../src/client/SettingsRoot.tsx'
+
+afterEach(cleanup)
+
+const DICT: Record<string, string> = {
+  'settings:trigger': 'Settings',
+  'settings:title': 'Settings',
+  'settings:close': 'Close',
+}
+
+type Row = { id: string; order: number; label: string }
+
+function mount({
+  wide = true,
+  rows = [
+    { id: 'general', order: 0, label: 'General' },
+    { id: 'models', order: 10, label: 'Models' },
+  ],
+}: { wide?: boolean; rows?: Row[] } = {}) {
+  // Mutable row store standing in for the ledger; bump() plays a change.
+  let current = rows
+  let version = 0
+  const listeners = new Set<() => void>()
+  const renderSlot = vi.fn(
+    ((_key: string, _owner: unknown, opts?: { only?: string }) =>
+      <div data-testid={`section-${opts?.only ?? 'all'}`} />) as SettingsRootComponentProps['renderSlot'],
+  )
+  // Global standard kit stubs: the shell consumes neither hook.
+  const unusedHook = (() => { throw new Error('unused by SettingsRoot') }) as never
+  const props: SettingsRootComponentProps = {
+    useSessions: unusedHook,
+    useWorkspaces: unusedHook,
+    wide,
+    translate: (ref) => DICT[ref] ?? ref,
+    sectionsVersion: () => version,
+    subscribeSections: (listener) => {
+      listeners.add(listener)
+      return () => { listeners.delete(listener) }
+    },
+    sections: () => current,
+    renderSlot,
+  }
+  const view = render(<SettingsRoot {...props} />)
+  const bump = (next: Row[]) => {
+    act(() => {
+      current = next
+      version += 1
+      for (const fn of [...listeners]) fn()
+    })
+  }
+  return { view, renderSlot, bump, listeners }
+}
+
+function openPanel() {
+  fireEvent.click(screen.getByRole('button', { name: 'Settings' }))
+}
+
+describe('SettingsRoot trigger', () => {
+  it('renders the wide row with the label and opens the dialog', () => {
+    mount()
+    const trigger = screen.getByRole('button', { name: 'Settings' })
+    expect(trigger.textContent).toContain('Settings')
+    expect(trigger.getAttribute('aria-expanded')).toBe('false')
+    fireEvent.click(trigger)
+    expect(screen.getByRole('dialog')).toBeTruthy()
+    expect(screen.getByRole('button', { name: 'Settings', expanded: true })).toBeTruthy()
+  })
+
+  it('drops the label in the rail state', () => {
+    mount({ wide: false })
+    expect(screen.getByRole('button', { name: 'Settings' }).textContent).toBe('')
+  })
+})
+
+describe('SettingsPanel close paths', () => {
+  it('closes via the header button', () => {
+    mount()
+    openPanel()
+    fireEvent.click(screen.getByRole('button', { name: 'Close' }))
+    expect(screen.queryByRole('dialog')).toBeNull()
+  })
+
+  it('closes via a mask click', () => {
+    mount()
+    openPanel()
+    const dialog = screen.getByRole('dialog')
+    fireEvent.click(dialog.parentElement!.firstElementChild!)
+    expect(screen.queryByRole('dialog')).toBeNull()
+  })
+
+  it('closes via document-level Escape and unhooks the listener with the panel', () => {
+    mount()
+    openPanel()
+    fireEvent.keyDown(document, { key: 'Escape' })
+    expect(screen.queryByRole('dialog')).toBeNull()
+    // Ignored while closed (listener removed with the panel) and non-Escape
+    // keys are ignored while open.
+    fireEvent.keyDown(document, { key: 'Escape' })
+    openPanel()
+    fireEvent.keyDown(document, { key: 'Enter' })
+    expect(screen.getByRole('dialog')).toBeTruthy()
+  })
+
+  it('lands focus on the close button when the dialog opens', () => {
+    mount()
+    openPanel()
+    expect(document.activeElement).toBe(screen.getByRole('button', { name: 'Close' }))
+  })
+})
+
+describe('SettingsPanel navigation', () => {
+  it('projects rows, marks the first active, and renders only that section', () => {
+    mount()
+    openPanel()
+    expect(screen.getByRole('button', { name: 'General' }).getAttribute('aria-current')).toBe('true')
+    expect(screen.getByRole('button', { name: 'Models' }).getAttribute('aria-current')).toBeNull()
+    expect(screen.getByTestId('section-general')).toBeTruthy()
+  })
+
+  it('switches the rendered section on nav click', () => {
+    mount()
+    openPanel()
+    fireEvent.click(screen.getByRole('button', { name: 'Models' }))
+    expect(screen.getByRole('button', { name: 'Models' }).getAttribute('aria-current')).toBe('true')
+    expect(screen.getByTestId('section-models')).toBeTruthy()
+    expect(screen.queryByTestId('section-general')).toBeNull()
+  })
+
+  it('falls back to the first row when the active entry unregisters', () => {
+    const { bump } = mount()
+    openPanel()
+    fireEvent.click(screen.getByRole('button', { name: 'Models' }))
+    bump([{ id: 'general', order: 0, label: 'General' }])
+    expect(screen.queryByRole('button', { name: 'Models' })).toBeNull()
+    expect(screen.getByTestId('section-general')).toBeTruthy()
+  })
+
+  it('renders an empty content column when the ledger is empty', () => {
+    const { renderSlot } = mount({ rows: [] })
+    openPanel()
+    expect(screen.getByRole('dialog')).toBeTruthy()
+    expect(renderSlot).not.toHaveBeenCalled()
+  })
+
+  it('drops the ledger subscription on unmount', () => {
+    const { view, listeners } = mount()
+    expect(listeners.size).toBe(1)
+    view.unmount()
+    expect(listeners.size).toBe(0)
+  })
+})