Function fire_break 

pub fn fire_break(
    app: &AppHandle,
    current_break: &Arc<Mutex<Option<BreakEvent>>>,
    kind: BreakKind,
    duration_secs: u64,
    enforceable: bool,
    placement: MonitorPlacement,
    windowed: bool,
    manual_finish: bool,
    postpone_available: bool,
    hints: Vec<String>,
    hint_rotate_seconds: u64,
    health_intensity: f32,
)

Build a BreakEvent, stash it in current_break, position an overlay window on each selected monitor, and emit break:start to the renderer. Used directly for sleep/resume-last paths; normal scheduled breaks go through deliver_break instead.