fix(dump): correct DI wiring, config types, and runtime version query

src/Service/DumpBinaryLocator.php

@@ -40,6 +40,9 @@ class DumpBinaryLocator
 
     private function isMariaDb(): bool
     {
-        return MySqlVariant::isMariaDb($this->connection->getServerVersion());
+        // Connection::getServerVersion() is private in the DBAL version this
+        // repo pins against — SELECT VERSION() is the stable public way to get
+        // the same string.
+        return MySqlVariant::isMariaDb((string) $this->connection->fetchOne('SELECT VERSION()'));
     }
 }