Two timer mutables (`scheduledPauseTimer`, `scheduledResumeTimer`) plus
the three clear helpers move into `src/store/scheduleTimers.ts`. The
module also gains `schedulePauseTimer(delayMs, onFire)` /
`scheduleResumeTimer(delayMs, onFire)` so callers no longer need to do
the `window.setTimeout(...) as unknown as number` cast or null the
handle inside the fire callback — the module auto-clears its own
reference before invoking the user callback.
`schedulePauseIn` / `scheduleResumeIn` store actions are now four lines
shorter each and don't reach into the timer mutables.
playerStore 3389 → 3369 LOC. 9 focused tests cover schedule + fire +
clear + replace-on-reschedule + independence between the two timers.
Frank Stellmacher