[Tenshock]

Summary

Restores the Nix development environment on current nixpkgs, migrates the project configuration to pnpm 11, and pins flake inputs for reproducible development shells.

Motivation

direnv allow failed because pkgs.nodePackages was removed from nixpkgs. The pnpm 11 configuration also produced warnings because pnpm no longer reads configuration from package.json#pnpm.

Changes

• replace pkgs.nodePackages.pnpm with pkgs.pnpm_11
• migrate pnpm settings from .npmrc to pnpm-workspace.yaml
• remove the obsolete package.json#pnpm configuration
• add flake.lock to pin nixpkgs and flake-utils

Testing

• direnv reload
• nix flake check --no-build
• nix build .#devShells.x86_64-linux.default --no-link

Breaking changes

None

Checklist

• I have read CLAUDE.md and followed the project's conventions.
• I have added or updated tests for the change.
• I have added or updated documentation where user-visible behavior changed.
• If this is a user-visible change, I have run pnpm changeset and committed
  the result.
• If this is a breaking change, I have flagged it above and the changeset is
  marked accordingly.
• I have re-read my own diff and removed dead code, debug prints, and stale
  comments.
• If I used an LLM to draft this PR, I have verified each change myself, this
  PR represents real work that warrants a maintainer's review, and I am
  willing to defend each line in review.

[github-actions]

Hi @Tenshock, thanks for the contribution.

This PR description does not match the project's PR template, so the PR has been auto-closed. Specifically:

• The PR description is missing the template anchor comment (<!-- pr-template:v1 -->). Please use the official PR template.

How to fix this

Please edit the PR description and restore the template structure. You can copy the template from .github/pull_request_template.md in this repository. Once the description is valid, this workflow will reopen the PR automatically.

Why we enforce this

PR templates exist so reviewers can understand the change without reverse-engineering the diff. Stripped-out or AI-generated boilerplate descriptions consume reviewer time without producing actionable signal. Repeated low-effort or AI-slop submissions from the same account may result in being blocked from this repository.

If you believe this auto-close is in error, please leave a comment explaining and a maintainer will take a look.

[github-actions]

Thanks for updating the description — the template now looks valid. A maintainer will review from here.

[baseballyama]

Thanks! Verified locally: pnpm install --frozen-lockfile, typecheck and build pass on pnpm 11.10.0 with no config warnings, and the moved settings resolve from pnpm-workspace.yaml.