CREATE TABLE IF NOT EXISTS poll_response (
  id BIGINT UNSIGNED NOT NULL AUTO_INCREMENT,
  poll_type VARCHAR(32) NOT NULL,
  session_uuid CHAR(36) NOT NULL,
  item_index INT NOT NULL,
  item_file VARCHAR(255) NOT NULL,
  choice VARCHAR(64) NOT NULL,
  user_agent VARCHAR(255) DEFAULT NULL,
  ip_hash CHAR(64) DEFAULT NULL,
  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (id),
  KEY idx_poll_item (poll_type, item_index),
  KEY idx_created (created_at)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;