refactor(compat): Prüfbausteine nach src/Compatibility, Matrix und ManifestCheck generisch

Requirement, Call, ConstantRequirement, Mirror, Problem, FeatureStatus, CompatibilityMatrix, Manifest, ManifestCheck sowie Fingerprints und LineDiff liegen jetzt im divi-freien Kern. Neu: GlobalRequirement, CompatibilityMatrix::fromProblems(), ManifestCheck-Option signatures, DiviManifestCheck::create() und DiviAreas. Divi-Verhalten unverändert.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/Unit/Compatibility/CallTest.php

@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace LIT\MCP\Tests\Unit\Compatibility;
+
+use LIT\MCP\Compatibility\Call;
+use PHPUnit\Framework\TestCase;
+
+final class CallTest extends TestCase
+{
+    public static function sample(int $a, int $b = 0): void
+    {
+    }
+
+    private static function method(): string
+    {
+        return self::class . '::sample';
+    }
+
+    public function testAcceptsAnExistingFunctionWithAMatchingArgumentCount(): void
+    {
+        self::assertTrue((new Call('strlen', 1))->accepts());
+        self::assertTrue((new Call('sprintf', 5))->accepts(), 'variadic');
+    }
+
+    public function testRejectsAnArgumentCountThePlatformFunctionDoesNotTake(): void
+    {
+        self::assertFalse((new Call('strlen', 2))->accepts(), 'strlen takes one argument');
+        self::assertFalse((new Call('str_replace', 2))->accepts(), 'str_replace needs three');
+    }
+
+    public function testNullArgumentCountOnlyChecksExistence(): void
+    {
+        self::assertTrue((new Call('str_replace'))->accepts());
+    }
+
+    public function testMissingFunctionOrMethodIsRejected(): void
+    {
+        self::assertFalse((new Call('lit_mcp_missing_function'))->accepts());
+        self::assertFalse((new Call(self::class . '::missing'))->accepts());
+        self::assertFalse((new Call('Lit\Missing\Klass::method'))->accepts());
+    }
+
+    public function testChecksTheArgumentCountOfAMethod(): void
+    {
+        self::assertTrue((new Call(self::method(), 1))->accepts());
+        self::assertTrue((new Call(self::method(), 2))->accepts());
+        self::assertFalse((new Call(self::method(), 0))->accepts(), 'one required');
+        self::assertFalse((new Call(self::method(), 3))->accepts(), 'at most two');
+    }
+}