PnP support for Turbopack

[martinjlowm]

Goals

1. Support PnP-based module resolution using the BeforeResolve plugin type, enabling Yarn users to utilize Turbopack as part of Next.js for improved DX

Non-Goals

No response

Background

The documentation on https://nextjs.org/docs/architecture/turbopack states that Yarn PnP is not planned to be supported, however, that could have been an old statement and be a different situation now that a stable dev server landed with the Next.js 15 release.

Proposal

It seems like from 5d3f8e8 that resolution plugins can be injected to override how modules are resolved. This would presumably be the place to drop in a pnp-rs-based plugin (https://github.com/yarnpkg/pnp-rs) to account for a zip-based FS-layer.

Happy to contribute a plugin for pnp-rs, however, I'm not entirely sure what the best option architecture-wise would be to add plugins on-demand and load them only if necessary.