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/isSameYear.d.ts

@@ -0,0 +1,29 @@
+import type { ContextOptions, DateArg } from "./types.js";
+/**
+ * The {@link isSameYear} function options.
+ */
+export interface IsSameYearOptions extends ContextOptions<Date> {}
+/**
+ * @name isSameYear
+ * @category Year Helpers
+ * @summary Are the given dates in the same year?
+ *
+ * @description
+ * Are the given dates in the same year?
+ *
+ * @param laterDate - The first date to check
+ * @param earlierDate - The second date to check
+ * @param options - An object with options
+ *
+ * @returns The dates are in the same year
+ *
+ * @example
+ * // Are 2 September 2014 and 25 September 2014 in the same year?
+ * const result = isSameYear(new Date(2014, 8, 2), new Date(2014, 8, 25))
+ * //=> true
+ */
+export declare function isSameYear(
+  laterDate: DateArg<Date> & {},
+  earlierDate: DateArg<Date> & {},
+  options?: IsSameYearOptions | undefined,
+): boolean;