[jeffhandley]

Summary

Align validate-pat-pool.yml with the validator in dotnet/core (814392b4):

• Use the reviewed gh-aw setup v0.93.2 default Copilot CLI instead of independently pinning CLI 1.0.21.
• Probe with Auto routing, disable CLI auto-update, and allow 90 seconds instead of 30 seconds; remove the obsolete --effort=low argument.
• Report CLI setup/install failures explicitly rather than presenting untested PATs as pool failures.

Preserves Empty/Valid/Invalid/Unknown classification, the PAT secret wiring, schedule, environment, and permissions. Only the validator workflow changes; no agentic workflow/compiler or documentation updates are included.

Validation

• Validator file exactly matches the dotnet/core reference blob.
• YAML parsing and Bash syntax checks passed.
• Mocked checks passed for all four PAT statuses and six summary outcomes, including failed/skipped CLI installation.
• git diff --check passed.

Live PATs were not tested, and no workflow was dispatched.