Add TypeScript types for hooks

**Feature request**
It would be great to have serialization for lib.

**Use case**
Many users need this functionality for production deployments.

**Implementation idea**
Add a new config option `enable_serialization` with default `false`.

The title asks for TypeScript hook types, while the body asks for serialization and an enable_serialization config option; no files, tests, or entry points are named. First clarify which request is intended and where the relevant configuration and hooks live, then define completion as the requested behavior being covered by tests.

Written by the indexing model from the issue text.