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/locale/tr.d.cts

@@ -0,0 +1,15 @@
+import type { Locale } from "./types.js";
+/**
+ * @category Locales
+ * @summary Turkish locale.
+ * @language Turkish
+ * @iso-639-2 tur
+ * @author Alpcan Aydın [@alpcanaydin](https://github.com/alpcanaydin)
+ * @author Berkay Sargın [@berkaey](https://github.com/berkaey)
+ * @author Fatih Bulut [@bulutfatih](https://github.com/bulutfatih)
+ * @author Ismail Demirbilek [@dbtek](https://github.com/dbtek)
+ * @author İsmail Kayar [@ikayar](https://github.com/ikayar)
+ *
+ *
+ */
+export declare const tr: Locale;