fix: resolve all quality gate failures — i18n key, typography tokens, PHPStan errors, style

- Add missing i18n key "LDAP attribute map could not be encoded" (de+en)
- Replace raw font-weight/line-height with design tokens in app-topbar.css
- Fix import ordering in SchedulerRunService.php (php-cs-fixer)
- Fix PHPStan mock chain errors in DebitorDetailServiceTest and TenantSsoServiceTest (PHPUnit 12 API)
- Simplify redundant comparison in NotificationService dedupe window
- Add PHPStan type hint for mock callback array in SchedulerJobFailedNotificationListenerTest
- Fix undefined variable and add flow-analysis suppression in login().php
- Increase dev PHP memory_limit to 1G for PHPStan (prod stays 256M)

All 6 quality gates now pass: QG-001 (1618 tests), QG-002 (0 errors),
QG-003 (6630 assertions), QG-006 (0 fixable), QG-008, QG-009.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/notifications/lib/Module/Notifications/Service/NotificationService.php

@@ -236,7 +236,7 @@ class NotificationService
         }
 
         $windowMinutes = self::DEDUPE_TYPES[$type];
-        $windowMinutes = is_int($windowMinutes) && $windowMinutes > 0 ? $windowMinutes : self::DEDUPE_WINDOW_MINUTES;
+        $windowMinutes = is_int($windowMinutes) ? $windowMinutes : self::DEDUPE_WINDOW_MINUTES;
 
         $tenantScope = $tenantId !== null && $tenantId > 0 ? $tenantId : 0;
         $raw = implode('|', [