Distributed Job Scheduler / Calendar Service

Requirements Functional requirements: schedule(task_id, run_at_ts, payload) — register a task to execute at a later timestamp. Inputs are a task identifier, a scheduled timestamp, and an opaque payload; it returns the registered task record or an error. cancel(task_id) — remove a task provided it has not started running. It returns whether the task was canceled. query(window_start, window_end) — return tasks whose scheduled times fall inside the requested interval; this…