fix(server): stop large thread history from exhausting memory - #4948

Bugbot Analysis Progress (5m 57s elapsed)

✅ Gathered PR context (8s)
✅ Completed bug detection (5m 48s)
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Final Result: Bugbot completed review - no issues found! ✅

Request ID: serverGenReqId_97dd88c4-ed11-4e5e-a3e2-4e4f09f31743