Every now and then `pnpm` disappears - proper way to remedy?

I just updated my editor, a fork of VS Code (Devin IDE, formerly Windsurf). And I've also been playing with Mojo where I had to clean up a mess involving old installs and remnants of `sv` and `pixi`.

It seems that one of the above things had the side-effect of "losing" `pnpm` somehow. This happened a month or two ago as well and I don't remember what may have led up to it that time.

```
% just sort-config-settings && just format && cargo clippy && cargo test
Sorted default_config.json child settings by name.
cargo fmt
pnpm format
sh: pnpm: command not found
error: Recipe `format` failed on line 43 with exit code 127
%
```
Is this something `just setup` should fix? I'm on macOS Tahoe and I never use homebrew on this machine.

In fact, `just setup` just finished and it also failed due to `pnpm` missing!
```
% just setup
[INFO]: 🎯 Checking for the Wasm target...
[INFO]: 🌀 Compiling to Wasm...
[INFO]: ⬇️ Installing wasm-bindgen...
[INFO]: Optimizing wasm binaries with `wasm-opt`...
[INFO]: Optional fields missing from Cargo.toml: 'description', 'license'. These are not necessary, but recommended
[INFO]: ✨ Done in 3m 22s
[INFO]: 📦 Your wasm pkg is ready to publish at /Users/hippietrail/harper/harper-wasm/pkg.
[WARN]: ⚠️ There's a newer version of wasm-pack available, the new version is: 0.15.0, you are using: 0.13.1. To update, navigate to: https://rustwasm.github.io/wasm-pack/installer/
[INFO]: 🎯 Checking for the Wasm target...
[INFO]: 🌀 Compiling to Wasm...
[INFO]: ⬇️ Installing wasm-bindgen...
[INFO]: Optimizing wasm binaries with `wasm-opt`...
[INFO]: Optional fields missing from Cargo.toml: 'description', 'license'. These are not necessary, but recommended
[INFO]: ✨ Done in 1m 52s
[INFO]: 📦 Your wasm pkg is ready to publish at /Users/hippietrail/harper/harper-wasm/pkg.
[WARN]: ⚠️ There's a newer version of wasm-pack available, the new version is: 0.15.0, you are using: 0.13.1. To update, navigate to: https://rustwasm.github.io/wasm-pack/installer/
/var/folders/k3/12zzpg7j4k347xdnnykffpd80000gn/T/just-HXajpi/build-harperjs: line 89: pnpm: command not found
error: Recipe `build-harperjs` failed with exit code 127
```
I tried to install pnpm the way it recommends:
```
% curl -fsSL https://get.pnpm.io/install.sh | sh -
==> Downloading pnpm 12.4.1
Installing pnpm CLI globally from /var/folders/k3/12zzpg7j4k347xdnnykffpd80000gn/T/tmp.UQdTT6lys0
 ERROR  The configured global bin directory "/Users/hippietrail/Library/pnpm" is not in PATH
For help, run: pnpm help add
Error: × Failed to install pnpm globally (exit code 1)

Install Error!
```

Start by inspecting the `format`, `setup`, and `build-harperjs` recipes, including the failing `pnpm` calls and the reported line 43. Reproduce the setup with `pnpm` absent from PATH; done means the project either handles the dependency correctly or clearly reports the required installation and PATH setup.

Written by the indexing model from the issue text.