Pass excludeUserID to CheckTimeBlockerOverlap in AdminReserveSlotHandler, CreateBookingHandler, EditBookingHandler, AdminRescheduleBookingHandler, AdminCreateBookingForUserHandler, AdminApproveEditRequestHandler, and ReserveSlotHandler. Also clean up stale reservations before overlap check in AdminReserveSlotHandler and ReserveSlotHandler via db.Conn.Exec for cross-connection visibility. Improve error handling in RequestEditHandler's service update block. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>