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/fp/endOfYearWithOptions.cjs

@@ -0,0 +1,8 @@
+"use strict";
+exports.endOfYearWithOptions = void 0;
+
+var _index = require("../endOfYear.cjs");
+var _index2 = require("./_lib/convertToFP.cjs"); // This file is generated automatically by `scripts/build/fp.ts`. Please, don't change it.
+
+const endOfYearWithOptions = (exports.endOfYearWithOptions = (0,
+_index2.convertToFP)(_index.endOfYear, 2));