* docs: reframe project as the official pnpm rewrite
- rewrite the top-level README around the pnpm-rewrite framing and a
two-phase roadmap, dropping the stale TODO list
- move debugging, testing, and benchmarking sections into CONTRIBUTING.md
- add a README to the `npm/pacquet` package and update its description
and keywords
- update the `AGENTS.md` cross-reference for the relocated benchmark
instructions
* docs: surface "not production-ready" warning at the top of READMEs
Per review feedback, lift the in-development warning into the first
paragraph of `npm/pacquet/README.md` (with bold emphasis so it stays
visible on the npm registry page) and add a matching admonition near
the top of the workspace `README.md`. The goal is to make the
project's status unmissable for anyone landing on either page.
* docs(npm): mark the npm package description as a preview
* docs(npm): note the package is not production-ready in its description