feat: plugin scaffold with dependency check

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01At3V6SjwbMe6eMzVGW3Hs7

tests/Unit/DependenciesTest.php

@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Tests\Unit;
+
+use LIT\MCP\Dependencies;
+
+final class DependenciesTest extends TestCase
+{
+    public function testReportsNothingMissingWhenAllClassesExist(): void
+    {
+        $deps = new Dependencies(static fn (string $class): bool => true);
+
+        self::assertSame([], $deps->missing());
+    }
+
+    public function testNamesEveryMissingComponent(): void
+    {
+        $deps = new Dependencies(static fn (string $class): bool => false);
+
+        self::assertSame(
+            ['wordpress/mcp-adapter', 'wp-media/mcp-oauth', 'WordPress Abilities API'],
+            $deps->missing()
+        );
+    }
+}