fix(server): log a bounded category when replay-guard pruning fails

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Y1jWssjvT14xf2uw1daK7Z
a929298ed3Claude committed on 9/25/2026, 11:41:19 PMparent252fd53
1 file changedLine totals unavailable