feat: add sync context and operation state

tests/Unit/Sync/SyncStateRepositoryTest.php

@@ -0,0 +1,46 @@
+<?php
+/**
+ * Tests for sync state persistence.
+ *
+ * @package WPContentSync
+ */
+
+namespace WPContentSync\Tests\Unit\Sync;
+
+use PHPUnit\Framework\TestCase;
+use WPContentSync\Sync\SyncOperationState;
+use WPContentSync\Sync\SyncStateRepository;
+
+class SyncStateRepositoryTest extends TestCase {
+	protected function tearDown(): void {
+		unset( $GLOBALS['wpcs_test_transients'], $GLOBALS['wpcs_test_transient_expiration'] );
+
+		parent::tearDown();
+	}
+
+	public function test_it_saves_and_reads_operation_state(): void {
+		$repository = new SyncStateRepository();
+		$state      = SyncOperationState::running( 'operation-1', 'posts', 2, 10 );
+
+		$repository->save( $state );
+
+		$loaded = $repository->get( 'operation-1' );
+
+		self::assertInstanceOf( SyncOperationState::class, $loaded );
+		self::assertSame( 'operation-1', $loaded->operationId() );
+		self::assertSame( 'posts', $loaded->currentBucket() );
+		self::assertSame( 2, $loaded->processed() );
+		self::assertSame( 10, $loaded->total() );
+		self::assertSame( 'running', $loaded->status() );
+	}
+
+	public function test_it_deletes_operation_state(): void {
+		$repository = new SyncStateRepository();
+		$repository->save( SyncOperationState::completed( 'operation-1', 10, 10 ) );
+
+		$repository->delete( 'operation-1' );
+
+		self::assertNull( $repository->get( 'operation-1' ) );
+		self::assertArrayNotHasKey( 'wpcs_sync_state_operation-1', $GLOBALS['wpcs_test_transient_expiration'] );
+	}
+}