bug: ERR_PNPM_FETCH_403

Since a few days (wild guess) we are facing some flakiness with the GitHub action.

Here is an example https://github.com/podman-desktop/podman-desktop/actions/runs/17240020861/job/48916866994?pr=13719, we had to relaunch 3 time the action for it to pass.

The logs

Run pnpm/action-setup@a7487c7e89a18df4991f7f222e4898a00d66ddda
  with:
    run_install: false
    dest: ~/setup-pnpm
    package_json_file: package.json
    standalone: false
Running self-installer...
   ERR_PNPM_FETCH_403  GET https://registry.npmjs.org/pnpm: Forbidden - 403
  
  This error happened while installing a direct dependency of /home/runner/setup-pnpm
  
  No authorization header was set for the request.
  
  No authorization settings were found in the configs.
  Try to log in to the registry by running "pnpm login"
  or add the auth tokens manually to the ~/.npmrc file.
Error: Something went wrong, self-installer exits with code 1
Installation Completed!

Start with the referenced GitHub Actions run and the pnpm/action-setup entry point, then inspect the setup inputs including package.json and the self-installer log. Done means identifying a reproducible cause for the intermittent registry 403 and verifying that the action completes reliably without relaunches.