refactor(01-tech-debt): extract AllegroTokenManager and StringHelper

Phase 1 complete (2/2 plans):

- Plan 01-01: Extract AllegroTokenManager — OAuth token logic
  centralized from 4 classes into dedicated manager class

- Plan 01-02: Extract StringHelper — nullableString/normalizeDateTime/
  normalizeColorHex extracted from 15+ classes into App\Core\Support\StringHelper;
  removed 19 duplicate private methods

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

src/Modules/Orders/OrdersController.php

@@ -8,6 +8,7 @@ use App\Core\Http\Response;
 use App\Core\I18n\Translator;
 use App\Core\Security\Csrf;
 use App\Core\View\Template;
+use App\Core\Support\StringHelper;
 use App\Modules\Auth\AuthService;
 use App\Modules\Shipments\ShipmentPackageRepository;
 
@@ -344,7 +345,7 @@ final class OrdersController
 
         foreach ($config as $group) {
             $items = [];
-            $groupColor = $this->normalizeColorHex((string) ($group['color_hex'] ?? '#64748b'));
+            $groupColor = StringHelper::normalizeColorHex((string) ($group['color_hex'] ?? '#64748b'));
             $groupItems = is_array($group['items'] ?? null) ? $group['items'] : [];
             foreach ($groupItems as $status) {
                 $code = strtolower(trim((string) ($status['code'] ?? '')));
@@ -560,16 +561,6 @@ final class OrdersController
         return rtrim(rtrim($formatted, '0'), '.');
     }
 
-    private function normalizeColorHex(string $value): string
-    {
-        $trimmed = trim($value);
-        if (preg_match('/^#[0-9a-fA-F]{6}$/', $trimmed) === 1) {
-            return strtolower($trimmed);
-        }
-
-        return '#64748b';
-    }
-
     /**
      * @return array<string, string>
      */

src/Modules/Orders/OrdersRepository.php

@@ -3,6 +3,7 @@ declare(strict_types=1);
 
 namespace App\Modules\Orders;
 
+use App\Core\Support\StringHelper;
 use PDO;
 use Throwable;
 
@@ -370,7 +371,7 @@ final class OrdersRepository
             if (!isset($groupMap[$groupId])) {
                 $groupMap[$groupId] = [
                     'name' => trim((string) ($row['group_name'] ?? '')),
-                    'color_hex' => $this->normalizeColorHex((string) ($row['group_color_hex'] ?? '#64748b')),
+                    'color_hex' => StringHelper::normalizeColorHex((string) ($row['group_color_hex'] ?? '#64748b')),
                     'items' => [],
                 ];
             }
@@ -780,13 +781,4 @@ final class OrdersRepository
         return $code;
     }
 
-    private function normalizeColorHex(string $value): string
-    {
-        $trimmed = trim($value);
-        if (preg_match('/^#[0-9a-fA-F]{6}$/', $trimmed) === 1) {
-            return strtolower($trimmed);
-        }
-
-        return '#64748b';
-    }
 }