Add OpenAPI docs, frontend, migrations, and API updates

- OpenAPI: add missing endpoints (add-from-url, subscriptions, public availability)
- OpenAPI: CalendarSubscription schema, Subscriptions tag
- Frontend app
- Migrations: count_for_availability, subscriptions_sync, user_preferences, calendar_settings
- Config, rate limit, auth, calendar, booking, ICS, availability, user service updates

Made-with: Cursor

frontend/node_modules/date-fns/addISOWeekYears.d.cts

@@ -0,0 +1,37 @@
+import type { ContextOptions, DateArg } from "./types.js";
+/**
+ * The {@link addISOWeekYears} function options.
+ */
+export interface AddISOWeekYearsOptions<DateType extends Date = Date>
+  extends ContextOptions<DateType> {}
+/**
+ * @name addISOWeekYears
+ * @category ISO Week-Numbering Year Helpers
+ * @summary Add the specified number of ISO week-numbering years to the given date.
+ *
+ * @description
+ * Add the specified number of ISO week-numbering years to the given date.
+ *
+ * ISO week-numbering year: http://en.wikipedia.org/wiki/ISO_week_date
+ *
+ * @typeParam DateType - The `Date` type, the function operates on. Gets inferred from passed arguments. Allows to use extensions like [`UTCDate`](https://github.com/date-fns/utc).
+ *
+ * @param date - The date to be changed
+ * @param amount - The amount of ISO week-numbering years to be added.
+ * @param options - An object with options
+ *
+ * @returns The new date with the ISO week-numbering years added
+ *
+ * @example
+ * // Add 5 ISO week-numbering years to 2 July 2010:
+ * const result = addISOWeekYears(new Date(2010, 6, 2), 5)
+ * //=> Fri Jun 26 2015 00:00:00
+ */
+export declare function addISOWeekYears<
+  DateType extends Date,
+  ResultDate extends Date = DateType,
+>(
+  date: DateArg<DateType>,
+  amount: number,
+  options?: AddISOWeekYearsOptions<ResultDate> | undefined,
+): ResultDate;