Replace the signal-as-event live-reload scheduler with a runner-driven model.
The `resolveTrack` loader schedules its resolve work on a new `RecurringRunner`
that re-runs the task on an injected `reschedule` policy; the separate
`scheduleTrackReload` behavior and its per-type reload-epoch signals are deleted.
Core (`core/tasks`):
- `Task.run()` is now memoized (runs once, shares the result across calls) and
gains `clone()` (fresh, pending, structurally identical) — added to `TaskLike`.
- `RecurringRunner`: single-slot, id-keyed (dedup same id / abort-and-replace on
new id), time-free. Each cycle runs `Promise.all([task.run(), reschedule(task,
previous, signal)])` and re-runs a `clone()` while reschedule resolves `true`.
- `Reschedule<T> = (task, previous, signal) => PromiseLike<boolean>` — invoked
concurrently with the run, observes it via the memoized `run()`, owns its delay.
- `delayedReschedule(cadence)` builds a Reschedule from a pure ms-cadence fn,
start-anchored (subtracts the run's elapsed) so reloads are measured from
load-start per RFC 8216 §6.3.4, preserving half-on-unchanged.
Supporting:
- `@videojs/utils/time`: add cancellable `sleep(ms, signal)`.
- `media/hls/reload-policy`: `mediaPlaylistReloadDelay` (pure cadence; relocated
scheduler logic — target-duration, half-on-unchanged, stop-on-ENDLIST, retry).
- `resolve-track`: baked universal completeness gate + injected `reschedule`;
engine composes `delayedReschedule(mediaPlaylistReloadDelay)`.
WIP: not fully validated end-to-end against a live stream through this path.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
