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/startOfYesterday.d.ts

@@ -0,0 +1,29 @@
+import type { ContextOptions } from "./types.js";
+/**
+ * The {@link startOfYesterday} function options.
+ */
+export interface StartOfYesterdayOptions<DateType extends Date = Date>
+  extends ContextOptions<DateType> {}
+/**
+ * @name startOfYesterday
+ * @category Day Helpers
+ * @summary Return the start of yesterday.
+ * @pure false
+ *
+ * @typeParam ContextDate - The `Date` type of the context function.
+ *
+ * @param options - An object with options
+ *
+ * @description
+ * Return the start of yesterday.
+ *
+ * @returns The start of yesterday
+ *
+ * @example
+ * // If today is 6 October 2014:
+ * const result = startOfYesterday()
+ * //=> Sun Oct 5 2014 00:00:00
+ */
+export declare function startOfYesterday<ContextDate extends Date>(
+  options?: StartOfYesterdayOptions<ContextDate> | undefined,
+): ContextDate;