fix: move sleep-timer to separate reducer

src/store/sleep-timer/index.ts

@@ -0,0 +1,23 @@
+import { PayloadAction, createSlice } from '@reduxjs/toolkit';
+
+export interface State {
+    date: number | null;
+}
+
+export const initialState: State = {
+    date: null,
+};
+
+const sleepTimer = createSlice({
+    name: 'sleep-timer',
+    initialState,
+    reducers: {
+        setTimerDate(state, action: PayloadAction<Date | null>) {
+            state.date = action.payload?.getTime() || null;
+        }
+    },
+});
+
+export const { setTimerDate } = sleepTimer.actions;
+
+export default sleepTimer;