Admin: PR review — fix(claude-doc-pr): close untrusted-checkout alerts #82 and #61 (PR #987)

[hilram7]

Admin review of netwrix/docs PR #987 (author: @DanPiazza-Netwrix) — merged 2026-05-22.

Applies security fixes from #986 to claude-doc-pr.yml to resolve two CodeQL high-severity alerts: adds fork guard to doc-review job (alert #82) and pins checkout to headRefOid SHA to eliminate TOCTOU race in doc-followup job (alert #61).

PR: #987