- Use tokio::task::block_in_place for safe sync→async bridging - Replace count(*) with count(1) in division context (QuestDB parser bug) - Add coalesce() for stddev NULL handling (single-row edge case) - Consolidate integration tests into single lifecycle test with DROP+CREATE - All 4 QuestDB tests pass against real QuestDB 8.2.3 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>