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/development/register-CBoanF80.d.ts

@@ -0,0 +1,30 @@
+import { R as RouteModule } from './instrumentation--6Pioq_G.js';
+
+/**
+ * Apps can use this interface to "register" app-wide types for React Router via interface declaration merging and module augmentation.
+ * React Router should handle this for you via type generation.
+ *
+ * For more on declaration merging and module augmentation, see https://www.typescriptlang.org/docs/handbook/declaration-merging.html#module-augmentation .
+ */
+interface Register {
+}
+type AnyParams = Record<string, string | undefined>;
+type AnyPages = Record<string, {
+    params: AnyParams;
+}>;
+type Pages = Register extends {
+    pages: infer Registered extends AnyPages;
+} ? Registered : AnyPages;
+type AnyRouteFiles = Record<string, {
+    id: string;
+    page: string;
+}>;
+type RouteFiles = Register extends {
+    routeFiles: infer Registered extends AnyRouteFiles;
+} ? Registered : AnyRouteFiles;
+type AnyRouteModules = Record<string, RouteModule>;
+type RouteModules = Register extends {
+    routeModules: infer Registered extends AnyRouteModules;
+} ? Registered : AnyRouteModules;
+
+export type { Pages as P, RouteFiles as R, RouteModules as a, Register as b };