Feature request: worker-less mode or test mock for @powersync/node

[mikecfisher]

Hi team, I'm using PowerSync with TanStack DB in a Next.js app and run my tests with Bun.

The problem: @powersync/node uses comlink + worker_threads internally, and Bun's worker_threads implementation has serialization bugs that cause TypeError: Unserializable return value when trying to initialize a PowerSync database.

Bun's worker support is still experimental (tracked in oven-sh/bun#15964) and there's no workaround on their side in the near term.

What would help:

1. A worker-less mode for @powersync/node - even if slower, it would let us run integration tests
2. Or a lightweight test mock that implements AbstractPowerSyncDatabase using synchronous SQLite (like bun:sqlite or better-sqlite3 without workers)

I want to test our TanStack DB collections end-to-end without needing to spin up Vitest separately just for PowerSync tests. Happy to help if you point me in the right direction.