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/isSameSecond.cjs

@@ -0,0 +1,47 @@
+"use strict";
+exports.isSameSecond = isSameSecond;
+var _index = require("./startOfSecond.cjs");
+
+/**
+ * @name isSameSecond
+ * @category Second Helpers
+ * @summary Are the given dates in the same second (and hour and day)?
+ *
+ * @description
+ * Are the given dates in the same second (and hour and day)?
+ *
+ * @param laterDate - The first date to check
+ * @param earlierDate - The second date to check
+ *
+ * @returns The dates are in the same second (and hour and day)
+ *
+ * @example
+ * // Are 4 September 2014 06:30:15.000 and 4 September 2014 06:30.15.500 in the same second?
+ * const result = isSameSecond(
+ *   new Date(2014, 8, 4, 6, 30, 15),
+ *   new Date(2014, 8, 4, 6, 30, 15, 500)
+ * )
+ * //=> true
+ *
+ * @example
+ * // Are 4 September 2014 06:00:15.000 and 4 September 2014 06:01.15.000 in the same second?
+ * const result = isSameSecond(
+ *   new Date(2014, 8, 4, 6, 0, 15),
+ *   new Date(2014, 8, 4, 6, 1, 15)
+ * )
+ * //=> false
+ *
+ * @example
+ * // Are 4 September 2014 06:00:15.000 and 5 September 2014 06:00.15.000 in the same second?
+ * const result = isSameSecond(
+ *   new Date(2014, 8, 4, 6, 0, 15),
+ *   new Date(2014, 8, 5, 6, 0, 15)
+ * )
+ * //=> false
+ */
+function isSameSecond(laterDate, earlierDate) {
+  return (
+    +(0, _index.startOfSecond)(laterDate) ===
+    +(0, _index.startOfSecond)(earlierDate)
+  );
+}