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

boardwalk/dist/index.html

@@ -6,8 +6,8 @@
     <meta name="robots" content="noindex, nofollow" />
     <meta name="summer-admin-base" content="__SUMMER_ADMIN_BASE__" />
     <title>SummerCMS</title>
-    <script type="module" crossorigin src="./assets/index-BC0qEqbI.js"></script>
-    <link rel="stylesheet" crossorigin href="./assets/index-wkQq4mI5.css">
+    <script type="module" crossorigin src="./assets/index-BQShvn7O.js"></script>
+    <link rel="stylesheet" crossorigin href="./assets/index-BBZKA2Yr.css">
   </head>
   <body>
     <div id="app"></div>