Nexus upgrade design and refresh

src/App/functions.php

@@ -32,7 +32,11 @@ function user_theme(): string
     $stmt->execute(['id' => $clientId]);
     $row = $stmt->fetch(\PDO::FETCH_ASSOC);
     $theme = is_array($row) ? (string)($row['theme'] ?? '') : '';
-    return $theme !== '' ? $theme : 'light';
+    return match ($theme) {
+        'dark', 'night' => 'night',
+        'light', 'day', '' => 'day',
+        default => $theme,
+    };
 }
 
 function set_user_theme(string $theme): void
@@ -64,14 +68,12 @@ function current_module_name(): ?string
 
 function auth_enabled(): bool
 {
-    return app()->config()->authEnabled;
+    return app()->auth()->isEnabled();
 }
 
 function auth_user(): ?array
 {
-    $session = app()->session();
-    $session->start();
-    return $_SESSION['auth_user'] ?? null;
+    return app()->auth()->user();
 }
 
 function auth_display_name(): string