migrate lib/datetime.js to ts

src/components/mobile/DateRangeSelectionSheet.vue

@@ -69,7 +69,7 @@ import {
     getTimezoneOffsetMinutes,
     getBrowserTimezoneOffsetMinutes,
     getDateRangeByDateType
-} from '@/lib/datetime.js';
+} from '@/lib/datetime.ts';
 
 export default {
     props: [

src/components/mobile/DateTimeSelectionSheet.vue

@@ -63,7 +63,7 @@ import {
     getTimezoneOffsetMinutes,
     getTimeValues,
     getCombinedDateAndTimeValues
-} from '@/lib/datetime.js';
+} from '@/lib/datetime.ts';
 import { createInlinePicker } from '@/lib/ui/mobile.js';
 
 export default {

src/components/mobile/MonthRangeSelectionSheet.vue

@@ -55,7 +55,7 @@ import {
     getThisYearFirstUnixTime,
     getYearMonthFirstUnixTime,
     getYearMonthLastUnixTime
-} from '@/lib/datetime.js';
+} from '@/lib/datetime.ts';
 
 export default {
     props: [

src/components/mobile/TrendsBarChart.vue

@@ -101,7 +101,7 @@ import {
     getYearMonthFirstUnixTime,
     getYearMonthLastUnixTime,
     getDateTypeByDateRange
-} from '@/lib/datetime.js';
+} from '@/lib/datetime.ts';
 import {
     sortStatisticsItems,
     getAllDateRanges