NPM package in subdirectory of repo does not work

Here is a repo where the NPM package is in a subdir (in this case apex): https://github.com/eighty4/eighty4.tech

When trying pnpm/action-setup I've run through variations of the config without any way of getting past the action failing looking for the pnpm lockfile at the repository root. Here are variations I've tried.

As a user I would expect just setting package_json_file path would work:

      - uses: actions/checkout@v4
      - uses: pnpm/action-setup@v4
        with:
          package_json_file: apex/package.json

I tried changing the cwd of run_install:

      - uses: actions/checkout@v4
      - uses: pnpm/action-setup@v4
        with:
          package_json_file: apex/package.json
          run_install: |
            - cwd: apex
              args: []

Even with run_install: false it still fails on the missing repository root pnpm lock file:

      - uses: actions/checkout@v4
      - uses: pnpm/action-setup@v4
        with:
          package_json_file: apex/package.json
          run_install: false

Am I overlooking a configuration for this project structure to work with pnpm/action-setup?

The issue names the package_json_file and run_install inputs but no repository files or tests. Start by reproducing the failure with the linked eighty4.tech repository and inspect how pnpm/action-setup resolves the package and lockfile paths. Done means a package in a subdirectory can be set up without requiring a root pnpm lockfile.