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/setMilliseconds.js

@@ -0,0 +1,36 @@
+import { toDate } from "./toDate.js";
+
+/**
+ * The {@link setMilliseconds} function options.
+ */
+
+/**
+ * @name setMilliseconds
+ * @category Millisecond Helpers
+ * @summary Set the milliseconds to the given date.
+ *
+ * @description
+ * Set the milliseconds to the given 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).
+ * @typeParam ResultDate - The result `Date` type, it is the type returned from the context function if it is passed, or inferred from the arguments.
+ *
+ * @param date - The date to be changed
+ * @param milliseconds - The milliseconds of the new date
+ * @param options - The options
+ *
+ * @returns The new date with the milliseconds set
+ *
+ * @example
+ * // Set 300 milliseconds to 1 September 2014 11:30:40.500:
+ * const result = setMilliseconds(new Date(2014, 8, 1, 11, 30, 40, 500), 300)
+ * //=> Mon Sep 01 2014 11:30:40.300
+ */
+export function setMilliseconds(date, milliseconds, options) {
+  const _date = toDate(date, options?.in);
+  _date.setMilliseconds(milliseconds);
+  return _date;
+}
+
+// Fallback for modularized imports:
+export default setMilliseconds;