It appears that the repository has undergone several changes and renamings:

backend/node_modules/date-fns/differenceInCalendarISOWeeks.d.cts

@@ -1,35 +0,0 @@
-import type { ContextOptions, DateArg } from "./types.js";
-/**
- * The {@link differenceInCalendarISOWeeks} function options.
- */
-export interface DifferenceInCalendarISOWeeksOptions
-  extends ContextOptions<Date> {}
-/**
- * @name differenceInCalendarISOWeeks
- * @category ISO Week Helpers
- * @summary Get the number of calendar ISO weeks between the given dates.
- *
- * @description
- * Get the number of calendar ISO weeks between the given dates.
- *
- * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
- *
- * @param laterDate - The later date
- * @param earlierDate - The earlier date
- * @param options - An object with options
- *
- * @returns The number of calendar ISO weeks
- *
- * @example
- * // How many calendar ISO weeks are between 6 July 2014 and 21 July 2014?
- * const result = differenceInCalendarISOWeeks(
- *   new Date(2014, 6, 21),
- *   new Date(2014, 6, 6),
- * );
- * //=> 3
- */
-export declare function differenceInCalendarISOWeeks(
-  laterDate: DateArg<Date> & {},
-  earlierDate: DateArg<Date> & {},
-  options?: DifferenceInCalendarISOWeeksOptions | undefined,
-): number;