Add custom Introspector class to allow transactions

[samlaycock]

• I have verified my changes didn't break the example project.

Description

This dialect used the built-in Kysely SqliteIntrospector class as its introspector, which under the hood makes queries to the sqlite_master table, which in D1 is a no go - I've extended SqliteIntrospector into a D1Introspector to support using the table_list and table_info PRAGMAs to query table metadata instead.

Also, I've bumped up the version of kysely to the latest while I'm here as there were type discrepancies between 0.23.3 and 0.26.3.

[aidenwallis]

Would this be a breaking change? (Because of the kysely-d1 version bump?)

[atinux]

I can confirm that this PR actually fixes an issue to run migrations with better-auth and Cloudflare D1.

I don't think it's a breaking change but actually a fix, the kysely version difference is only in dev dependencies here.

Any chance to see this merged and release @aidenwallis ? 🙏

PS: thank you for making this great adapter ❤️

[samlaycock]

Sorry @aidenwallis, completely missed your response. Can confirm the version bump isn't a breaking change, it's only to have the correct typescript types.