switch to pnpm?

[NullVoxPopuli]

as we all know, yarn can't be trusted

[lifeart]

Since we are building a server and don't require dependencies to install it, I don't think this is a major improvement (we need to assess the possible risks well and update the editor extension at the same time as the server, but this may not work due to the peculiarities of publishing and building extensions).

But, I think it's a good issue to explore!