Feature Request: Better Error Handling Support

I'd like it to be a bit easier to handle errors thrown by pglite. Currently the [DatabaseError](https://github.com/electric-sql/pglite/blob/main/packages/pg-protocol/src/messages.ts#L147) class isn't exported and is bundled into the final library. The constructor name is obfuscated as well. So I can't reliably check if a thrown error is a `instanceof DatabaseError` or `error.constructor.name == "DatabaseError"`. I can check for the existence of certain fields on the error object, but I'd rather be able to use one of the previous methods.

I'd also really like the `DatabaseError` Typescript type to be exported by the library so that I can pull all of the properties off of the object in a typesafe way without using casting to my own user-land types.

Really enjoying Pglite though! Keep up the good work!