// Package scheduler runs feedkit sources and forwards their events to the
// daemon event bus.
//
// External API surface:
//   - Scheduler: runs configured polling and streaming jobs
//   - Job: one scheduler task bound to a source
//   - StreamExitPolicy: stream supervision policy for non-fatal exits
//   - StreamBackoff: restart pacing for supervised stream sources
//
// Optional helpers from helpers.go:
//   - JobFromSourceConfig: build a scheduler job from a configured source and
//     feedkit-owned scheduling params
//
// Poll sources are run on a fixed cadence with optional jitter. Stream sources
// are supervised long-lived workers. Their generic feedkit controls live under
// sources[].params:
//   - stream_exit_policy: restart|stop|fatal (default restart)
//   - stream_backoff_initial: positive duration (default 1s)
//   - stream_backoff_max: positive duration (default 1m)
//   - stream_backoff_jitter: non-negative duration (default 250ms)
//
// Stream sources can classify exits with sources.StreamRetryable and
// sources.StreamFatal. Plain errors are treated as retryable by default, while
// fatal exits are propagated from Scheduler.Run so the daemon can shut down.
package scheduler