feat(10-04): collapsible panel with flyout, user menu with logout, breadcrumbs and dark mode

- useSidebar: collapsed below 1100px (matchMedia) or by the admin's choice,
  persisted as a boolean under summer-admin.sidebar; the viewport never
  overwrites the stored choice
- SectionPanel collapse and rail expand buttons; SectionFlyout (role menu)
  opens on hover, focus, Enter or ArrowDown on a rail item, closes on Esc or
  about 200 ms after leaving and returns focus to the rail item
- Breadcrumbs with plugin, controller and record crumbs; UserMenu (Reka
  DropdownMenu) with initials, name, role and Wyloguj
- useAuth.logout POSTs /auth/logout, clears user, navigation and settings
  and routes to login even when the call fails
- applyColorScheme toggles .dark from prefers-color-scheme (no toggle, A6)
- newest toast first, 200 ms fade and scale for dialogs and toasts
- one relation-manager type constant in the registry
- shell smoke tests; tests default to a desktop, light matchMedia

admin/tests/setup.ts

@@ -4,3 +4,18 @@ const meta = document.createElement('meta')
 meta.setAttribute('name', 'summer-admin-base')
 meta.setAttribute('content', '/admin-test')
 document.head.appendChild(meta)
+
+// happy-dom's default viewport is 1024px wide, below the 1100px sidebar
+// breakpoint. Tests get a desktop, light-mode media environment; the shell
+// smoke test spies on matchMedia to simulate narrow or dark screens.
+window.matchMedia = (query: string): MediaQueryList =>
+  ({
+    matches: false,
+    media: query,
+    onchange: null,
+    addEventListener: () => undefined,
+    removeEventListener: () => undefined,
+    addListener: () => undefined,
+    removeListener: () => undefined,
+    dispatchEvent: () => false,
+  }) as MediaQueryList