🛠 Repo: Switch from lerna to npm workspaces

[JoshuaKGoldberg]

Tooling Suggestion Checklist

• I have tried restarting my IDE and the issue persists.
• I have pulled the latest main branch of the repository.
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Overview

This repository uses Lerna for workspace management. When it was first created, npm didn't yet support workspaces and Lerna was the industry leader. But today npm does have native workspace management: https://docs.npmjs.com/cli/using-npm/workspaces. So I don't think it's necessary to take on the overhead of a full monorepo manager like Lerna/Nx/Turborepo.

Proposal: let's drop Lerna and just use npm workspaces directoy?

Additional Info

No response