Function fire_scheduled_break 

pub(super) async fn fire_scheduled_break<R: Runtime>(
    app: &AppHandle<R>,
    sched: &Scheduler,
    s: &Settings,
    kind: BreakKind,
    fixed_key: Option<(String, u32)>,
)

Fire a scheduled micro/long break end to end: deliver it (see deliver_scheduled_break) and apply the post-fire timer bookkeeping under the timers lock (see record_scheduled_fire). fixed_key is Some((today, minute)) for a fixed-time fire (recording the dedupe key) or None for an interval fire; the fire Instant is stamped here.

Also the on-demand entry for “take a long break now” (#258): the start_long_break_now command calls this with Long/None so a user-initiated long break behaves exactly like a due one — same delivery, same re-anchor of both interval clocks — and never doubles up later.