The updates query now passes TanStack Query's abort signal to apiFetch, so closing the sheet while its read is pending aborts that GET. An immediate reopen then sends its own read instead of adopting the one sent before a newer event was stored, and marks seen only what that read returned. Closes MQ-176-01 (task 96e2dc3f-1f8a-4114-bcb5-e0f93c349165). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>