Persist gh PATH at Machine level for cross-step visibility

[Finesssee]

Summary

• persist gh install directory to both Machine and User PATH env vars (not just User)
• CircleCI runs each run step as a separate shell process; User-level PATH changes don't propagate to the next step
• Machine-level PATH is picked up by all new processes on the runner

Root cause

Pipeline #38: gh install step (102) succeeded and installed gh.exe to C:\Users\circleci\AppData\Local\gh\bin\gh.exe. But the publish step (103) could not find gh because the PATH change from the install step did not persist across CircleCI run steps. Setting only User-level PATH was insufficient.

Validation

• circleci config validate passed
• no version files changed

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