Split meta architecture contracts

tests/Architecture/AgentSystemContractSupport.php

@@ -0,0 +1,16 @@
+<?php
+
+namespace MintyPHP\Tests\Architecture;
+
+trait AgentSystemContractSupport
+{
+    /**
+     * @return array<string,mixed>
+     */
+    private function decodeAgentJson(string $path): array
+    {
+        $decoded = json_decode($this->readProjectFile($path), true);
+        $this->assertIsArray($decoded, 'Invalid JSON in ' . $path);
+        return $decoded;
+    }
+}