test: add base TestCase and bootstrap for in-memory SQLite

tests/bootstrap.php

@@ -0,0 +1,16 @@
+<?php
+
+// Test bootstrap for the DuckBrain development harness.
+// Run PHPUnit from the project root (autoload.php resolves config.php via cwd).
+
+require_once __DIR__ . '/../vendor/autoload.php';
+
+// Define DB constants BEFORE config.php so the test database wins over the
+// real configuration (config.php's define() warnings are suppressed by @).
+define('DB_TYPE', 'sqlite');
+define('DB_HOST', 'localhost');
+define('DB_NAME', ':memory:');
+define('DB_USER', '');
+define('DB_PASS', '');
+
+@require_once __DIR__ . '/../autoload.php';