feat(sync) : add DTOs and SyncStrategyInterface

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

src/DTO/SyncConfirmation.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\DTO;
+
+class SyncConfirmation
+{
+    public function __construct(
+        public readonly bool $confirmDeletions = false,
+        public readonly bool $confirmTypeChanges = false,
+    ) {}
+}

src/DTO/SyncExecutionResult.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\DTO;
+
+use JsonSerializable;
+
+class SyncExecutionResult implements JsonSerializable
+{
+    public function __construct(
+        public readonly int $itemsUpdated,
+        public readonly array $additions = [],
+        public readonly array $deletions = [],
+        public readonly array $modifications = [],
+    ) {}
+
+    public function jsonSerialize(): array
+    {
+        return [
+            'itemsUpdated'  => $this->itemsUpdated,
+            'additions'     => $this->additions,
+            'deletions'     => $this->deletions,
+            'modifications' => $this->modifications,
+        ];
+    }
+}

src/DTO/SyncPreviewResult.php

@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\DTO;
+
+use JsonSerializable;
+
+class SyncPreviewResult implements JsonSerializable
+{
+    public function __construct(
+        public readonly string $modelTypeId,
+        public readonly string $category,
+        public readonly int $itemCount,
+        public readonly array $additions = [],
+        public readonly array $deletions = [],
+        public readonly array $modifications = [],
+    ) {}
+
+    public function hasImpact(): bool
+    {
+        return array_sum($this->additions) > 0
+            || array_sum($this->deletions) > 0
+            || array_sum($this->modifications) > 0;
+    }
+
+    public function jsonSerialize(): array
+    {
+        return [
+            'modelTypeId'   => $this->modelTypeId,
+            'category'      => $this->category,
+            'itemCount'     => $this->itemCount,
+            'additions'     => $this->additions,
+            'deletions'     => $this->deletions,
+            'modifications' => $this->modifications,
+        ];
+    }
+}