Use SQLite in-memory database for tests

Switch from MySQL to SQLite for CI compatibility. The CI workflow
doesn't have a MySQL service, causing connection refused errors.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: relliv

tests/TestCase.php

@@ -75,7 +75,12 @@ protected function defineDatabaseSeeders()
 
     public function getEnvironmentSetUp($app)
     {
-        config()->set('database.connections.mysql.prefix', 'hasin_test_');
+        config()->set('database.default', 'testing');
+        config()->set('database.connections.testing', [
+            'driver' => 'sqlite',
+            'database' => ':memory:',
+            'prefix' => '',
+        ]);
 
         Schema::defaultStringLength(191);
         Factory::guessFactoryNamesUsing(