Simplify auto-transition queries in GetCurrentAndNextHandler by using bookings.end_time computed column instead of inline start_time + duration calculations. Remove ::text casts from end_time columns. Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent) Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>