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/react-router/dist/production/index-react-server-client.mjs

@@ -0,0 +1,59 @@
+/**
+ * react-router v7.13.1
+ *
+ * Copyright (c) Remix Software Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE.md file in the root directory of this source tree.
+ *
+ * @license MIT
+ */
+"use client";
+import {
+  AwaitContextProvider,
+  BrowserRouter,
+  Form,
+  HashRouter,
+  HistoryRouter,
+  Link,
+  Links,
+  MemoryRouter,
+  Meta,
+  NavLink,
+  Navigate,
+  Outlet,
+  Route,
+  Router,
+  RouterProvider,
+  Routes,
+  ScrollRestoration,
+  StaticRouter,
+  StaticRouterProvider,
+  WithComponentProps,
+  WithErrorBoundaryProps,
+  WithHydrateFallbackProps
+} from "./chunk-RJCJ3EYF.mjs";
+export {
+  BrowserRouter,
+  Form,
+  HashRouter,
+  Link,
+  Links,
+  MemoryRouter,
+  Meta,
+  NavLink,
+  Navigate,
+  Outlet,
+  Route,
+  Router,
+  RouterProvider,
+  Routes,
+  ScrollRestoration,
+  StaticRouter,
+  StaticRouterProvider,
+  AwaitContextProvider as UNSAFE_AwaitContextProvider,
+  WithComponentProps as UNSAFE_WithComponentProps,
+  WithErrorBoundaryProps as UNSAFE_WithErrorBoundaryProps,
+  WithHydrateFallbackProps as UNSAFE_WithHydrateFallbackProps,
+  HistoryRouter as unstable_HistoryRouter
+};