Database connection failed:

MySQL Error: SQLSTATE[HY000] [1698] Access denied for user 'root'@'localhost'

Please ensure:
1. PDO extension is installed (php-pdo)
2. MySQL PDO driver is installed (php-mysql or php-pdo-mysql)
3. MySQL database exists and credentials in config/config.php are correct
4. MySQL server is running and accessible

To check installed PDO drivers, run: php -m | grep pdo