Adopt Schema component in server handlers

tests/Schema/JsonRpc/RequestTest.php

@@ -0,0 +1,58 @@
+<?php
+
+/*
+ * This file is part of the official PHP MCP SDK.
+ *
+ * A collaboration between Symfony and the PHP Foundation.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Mcp\Tests\Schema\JsonRpc;
+
+use Mcp\Schema\JsonRpc\Request;
+use PHPUnit\Framework\TestCase;
+
+final class RequestTest extends TestCase
+{
+    public function testMetaAndIdAreLoopedThrough()
+    {
+        $requestImplementation = new class extends Request {
+            public static function getMethod(): string
+            {
+                return 'foo/bar';
+            }
+
+            public static function fromParams(?array $params): self
+            {
+                return new self();
+            }
+
+            protected function getParams(): ?array
+            {
+                return null;
+            }
+        };
+
+        $notification = $requestImplementation::fromArray([
+            'jsonrpc' => '2.0',
+            'id' => '12345',
+            'method' => 'foo/bar',
+            'params' => [
+                '_meta' => ['key' => 'value'],
+            ],
+        ]);
+
+        $expectedMeta = [
+            'jsonrpc' => '2.0',
+            'id' => '12345',
+            'method' => 'foo/bar',
+            'params' => [
+                '_meta' => ['key' => 'value'],
+            ],
+        ];
+
+        $this->assertSame($expectedMeta, $notification->jsonSerialize());
+    }
+}