Add menu enable toggle, user status, and mobile/UI polish

- Admin menu page: mobile item cards now put Actions in the top-right
  corner next to Status, matching the desktop row layout instead of
  stacking at the bottom; same treatment applied to announcements and
  users for consistency across all three admin lists
- Center button label text everywhere via .btn { justify-content: center }
  instead of one-off overrides
- Add a Disable/Enable Menu toggle to the admin menu toolbar; the public
  menu page shows its existing "menu being updated" message while disabled
- Add an Enabled/Disabled status to user accounts, with its own toggle
  badge, guardrails against disabling your own account or the last
  enabled account, and an immediate session kick for anyone disabled
  mid-session
- Fix the announcement banner / hero tagline "·" separators to hide only
  when their neighboring text actually wraps onto a different line,
  instead of a fixed breakpoint or always-on dot

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

admin/menu.php

@@ -135,6 +135,12 @@ function handle_delete_category(array $post): array
   return ['success' => true];
 }
 
+function handle_toggle_menu_enabled(): array
+{
+  set_menu_enabled(!is_menu_enabled());
+  return ['success' => true, 'menu_enabled' => is_menu_enabled()];
+}
+
 function handle_menu_action(string $action, array $post): array
 {
   return match ($action) {
@@ -145,6 +151,7 @@ function handle_menu_action(string $action, array $post): array
     'save_category' => handle_save_category($post),
     'move_category' => handle_move_category($post),
     'delete_category' => handle_delete_category($post),
+    'toggle_menu_enabled' => handle_toggle_menu_enabled(),
     default => ['success' => false, 'error' => 'Unknown action'],
   };
 }
@@ -167,6 +174,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'POST') {
 
 $categories = get_all_categories();
 $menuGrouped = get_full_menu(false);
+$menuEnabled = is_menu_enabled();
 ?>
 <!doctype html>
 <html lang="en">
@@ -213,6 +221,13 @@ $menuGrouped = get_full_menu(false);
       <div class="admin-toolbar">
         <button type="button" class="btn btn-primary btn-sm" id="btn-new-item">+ Add Menu Item</button>
         <button type="button" class="btn btn-outline btn-sm" id="btn-new-cat">+ Add Category</button>
+        <button type="button" class="btn btn-sm <?= $menuEnabled ? 'btn-danger' : 'btn-outline' ?>" id="btn-toggle-menu" data-enabled="<?= $menuEnabled ? '1' : '0' ?>">
+          <?= $menuEnabled ? 'Disable Menu' : 'Enable Menu' ?>
+        </button>
+      </div>
+
+      <div class="alert-error" id="menu-disabled-alert" role="status" <?= $menuEnabled ? 'hidden' : '' ?>>
+        Menu is disabled — the public menu page shows a "menu being updated" message instead of your items.
       </div>
 
       <div id="categories-container">