CREATE TABLE IF NOT EXISTS im_audit_logs (
  id              BIGINT NOT NULL AUTO_INCREMENT,
  actor_uid       BIGINT NOT NULL DEFAULT 0,
  actor_role      VARCHAR(64) NOT NULL DEFAULT '',
  action          VARCHAR(128) NOT NULL,
  target_type     VARCHAR(64) NOT NULL DEFAULT '',
  target_id       VARCHAR(128) NOT NULL DEFAULT '',
  before_snapshot JSON,
  after_snapshot  JSON,
  reason          VARCHAR(512) NOT NULL DEFAULT '',
  request_id      VARCHAR(64) NOT NULL DEFAULT '',
  ip              VARCHAR(64) NOT NULL DEFAULT '',
  user_agent      VARCHAR(512) NOT NULL DEFAULT '',
  metadata        JSON,
  created_at      DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
  PRIMARY KEY (id),
  INDEX idx_im_audit_logs_actor (actor_uid, id DESC),
  INDEX idx_im_audit_logs_action (action, id DESC),
  INDEX idx_im_audit_logs_target (target_type, target_id, id DESC),
  INDEX idx_im_audit_logs_request (request_id),
  INDEX idx_im_audit_logs_created (created_at, id DESC)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='IM租户审计日志';