Consistent Timestamp Format in Get-Schedule API

We’ve standardized how the get-schedule API returns time information, making it easier and more reliable to work with schedule data.

Unified timestamp format — All timestamps across programs, fillers, and overlay windows are now returned as ISO-8601 strings (YYYY-MM-DDTHH:mm:ssZ) with timezone offset included. Sorted and easier to consume — Responses are now sorted by start time in ascending order, and each program includes its duration in seconds. More reliable overlay timing — Resolved timezone handling issues that could occur when overlays ended at the edge of a window.