x/vulndb: potential Go vuln in os/exec: CVE-2025-47906

[neild]

File report and add CVE record for golang/go#74466

[gopherbot]

Change https://go.dev/cl/704476 mentions this issue: data/reports: add GO-2025-3956

[thatnealpatel]

Duplicate of #3946

[ethanalee-work]

Closing as report has been filed: https://go.dev/cl/704476