fix: update ZillizCloud benchmark with Cardinal backend results

Replace ZillizCloud-8cu-perf case_id=4/5 data with new Cardinal backend
benchmark results (level 1-9, 1M and 10M datasets, v2026.4). Remove
force_merge entries as Cardinal uses unified 4-segment architecture for 10M.

New results show significant QPS improvement:
- 1M: 13,316 QPS (was 9,704) at recall 0.938
- 10M: 7,385 QPS (was 3,957) at recall 0.938

Sort all leaderboard entries by (db_name, dataset, filter_ratio, qps DESC)
to fix line chart rendering. Remove one SQ4U 1M outlier (recall=0.84).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Ubuntu