Refactor bulk info provider: replace complex arrays with DTOs

- Add BulkSearchResponseDTO, FieldMappingDTO for type safety
- Use composition instead of inheritance in BulkSearchResultDTO
- Remove unnecessary BulkSearchRequestDTO
- Fix N+1 queries and API error handling
- Fix Add Mapping button functionality

src/Services/InfoProviderSystem/DTOs/BulkSearchResultDTO.php

@@ -1,32 +1,139 @@
 <?php
+/*
+ * This file is part of Part-DB (https://github.com/Part-DB/Part-DB-symfony).
+ *
+ *  Copyright (C) 2019 - 2023 Jan Böhmer (https://github.com/jbtronics)
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU Affero General Public License as published
+ *  by the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU Affero General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Affero General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
 
 declare(strict_types=1);
 
 namespace App\Services\InfoProviderSystem\DTOs;
 
+use App\Entity\Parts\ManufacturingStatus;
 use App\Entity\Parts\Part;
 
-class BulkSearchResultDTO extends SearchResultDTO
+/**
+ * Represents a search result from bulk search with additional context information.
+ * Uses composition instead of inheritance for better maintainability.
+ */
+readonly class BulkSearchResultDTO
 {
     public function __construct(
-        SearchResultDTO $baseDto,
-        public readonly ?string $sourceField = null,
-        public readonly ?string $sourceKeyword = null,
-        public readonly ?Part $localPart = null,
-        public readonly int $priority = 1
-    ) {
-        parent::__construct(
-            provider_key: $baseDto->provider_key,
-            provider_id: $baseDto->provider_id,
-            name: $baseDto->name,
-            description: $baseDto->description,
-            category: $baseDto->category,
-            manufacturer: $baseDto->manufacturer,
-            mpn: $baseDto->mpn,
-            preview_image_url: $baseDto->preview_image_url,
-            manufacturing_status: $baseDto->manufacturing_status,
-            provider_url: $baseDto->provider_url,
-            footprint: $baseDto->footprint
-        );
+        /** The base search result DTO containing provider data */
+        public SearchResultDTO $baseDto,
+        /** The field that was used to find this result */
+        public ?string $sourceField = null,
+        /** The actual keyword that was searched for */
+        public ?string $sourceKeyword = null,
+        /** Local part that matches this search result, if any */
+        public ?Part $localPart = null,
+        /** Priority for this search result */
+        public int $priority = 1
+    ) {}
+
+    // Delegation methods for SearchResultDTO properties
+    public function getProviderKey(): string
+    {
+        return $this->baseDto->provider_key;
+    }
+
+    public function getProviderId(): string
+    {
+        return $this->baseDto->provider_id;
+    }
+
+    public function getName(): string
+    {
+        return $this->baseDto->name;
+    }
+
+    public function getDescription(): string
+    {
+        return $this->baseDto->description;
+    }
+
+    public function getCategory(): ?string
+    {
+        return $this->baseDto->category;
+    }
+
+    public function getManufacturer(): ?string
+    {
+        return $this->baseDto->manufacturer;
+    }
+
+    public function getMpn(): ?string
+    {
+        return $this->baseDto->mpn;
+    }
+
+    public function getPreviewImageUrl(): ?string
+    {
+        return $this->baseDto->preview_image_url;
+    }
+
+    public function getPreviewImageFile(): ?FileDTO
+    {
+        return $this->baseDto->preview_image_file;
+    }
+
+    public function getManufacturingStatus(): ?ManufacturingStatus
+    {
+        return $this->baseDto->manufacturing_status;
+    }
+
+    public function getProviderUrl(): ?string
+    {
+        return $this->baseDto->provider_url;
+    }
+
+    public function getFootprint(): ?string
+    {
+        return $this->baseDto->footprint;
+    }
+
+    // Backwards compatibility properties for legacy code
+    public function __get(string $name): mixed
+    {
+        return match ($name) {
+            'provider_key' => $this->baseDto->provider_key,
+            'provider_id' => $this->baseDto->provider_id,
+            'name' => $this->baseDto->name,
+            'description' => $this->baseDto->description,
+            'category' => $this->baseDto->category,
+            'manufacturer' => $this->baseDto->manufacturer,
+            'mpn' => $this->baseDto->mpn,
+            'preview_image_url' => $this->baseDto->preview_image_url,
+            'preview_image_file' => $this->baseDto->preview_image_file,
+            'manufacturing_status' => $this->baseDto->manufacturing_status,
+            'provider_url' => $this->baseDto->provider_url,
+            'footprint' => $this->baseDto->footprint,
+            default => throw new \InvalidArgumentException("Property '{$name}' does not exist")
+        };
+    }
+
+    /**
+     * Magic isset method for backwards compatibility.
+     */
+    public function __isset(string $name): bool
+    {
+        return in_array($name, [
+            'provider_key', 'provider_id', 'name', 'description', 'category',
+            'manufacturer', 'mpn', 'preview_image_url', 'preview_image_file',
+            'manufacturing_status', 'provider_url', 'footprint'
+        ], true);
     }
 }