Update: QA Team membership

[suspect15]

Updates About Us doc with current QA members. Also adds a comma to "5000" mentioned below, that section probably should be revised/updated as its quite outdated.

[greptile-apps]

Greptile Summary

Updates the QA roster and formats “5,000” consistently.

Confidence Score: 5/5

The documentation-only changes appear safe to merge.

The roster remains alphabetical and linked documentation uses it as the canonical list.

_{Reviews (1): Last reviewed commit: "Update: QA Team membership" | Re-trigger Greptile}