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/hi/_lib/localize.d.ts

@@ -0,0 +1,37 @@
+import type { Localize } from "../../types.js";
+type hiLocaleNumberType =
+  | "\u0967"
+  | "\u0968"
+  | "\u0969"
+  | "\u096A"
+  | "\u096B"
+  | "\u096C"
+  | "\u096D"
+  | "\u096E"
+  | "\u096F"
+  | "\u0966";
+type enLocaleNumberType =
+  | "1"
+  | "2"
+  | "3"
+  | "4"
+  | "5"
+  | "6"
+  | "7"
+  | "8"
+  | "9"
+  | "0";
+type enHiLocaleNumberType = {
+  [enNumber in enLocaleNumberType]: hiLocaleNumberType;
+};
+type hiLocaleEnNumberType = {
+  [hiNumber in hiLocaleNumberType]: enLocaleNumberType;
+};
+export interface hiLocaleNumberValuesType {
+  locale: enHiLocaleNumberType;
+  number: hiLocaleEnNumberType;
+}
+export declare function localeToNumber(locale: string): number;
+export declare function numberToLocale(enNumber: number): string;
+export declare const localize: Localize;
+export {};