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/@babel/helper-validator-option/lib/index.js

@@ -0,0 +1,21 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+Object.defineProperty(exports, "OptionValidator", {
+  enumerable: true,
+  get: function () {
+    return _validator.OptionValidator;
+  }
+});
+Object.defineProperty(exports, "findSuggestion", {
+  enumerable: true,
+  get: function () {
+    return _findSuggestion.findSuggestion;
+  }
+});
+var _validator = require("./validator.js");
+var _findSuggestion = require("./find-suggestion.js");
+
+//# sourceMappingURL=index.js.map