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/enhanced-resolve/lib/createInnerContext.js

@@ -0,0 +1,46 @@
+/*
+	MIT License http://www.opensource.org/licenses/mit-license.php
+	Author Tobias Koppers @sokra
+*/
+
+"use strict";
+
+/** @typedef {import("./Resolver").ResolveContext} ResolveContext */
+
+/**
+ * @param {ResolveContext} options options for inner context
+ * @param {null | string} message message to log
+ * @returns {ResolveContext} inner context
+ */
+module.exports = function createInnerContext(options, message) {
+	let messageReported = false;
+	let innerLog;
+	if (options.log) {
+		if (message) {
+			/**
+			 * @param {string} msg message
+			 */
+			innerLog = (msg) => {
+				if (!messageReported) {
+					/** @type {((str: string) => void)} */
+					(options.log)(message);
+					messageReported = true;
+				}
+
+				/** @type {((str: string) => void)} */
+				(options.log)(`  ${msg}`);
+			};
+		} else {
+			innerLog = options.log;
+		}
+	}
+
+	return {
+		log: innerLog,
+		yield: options.yield,
+		fileDependencies: options.fileDependencies,
+		contextDependencies: options.contextDependencies,
+		missingDependencies: options.missingDependencies,
+		stack: options.stack,
+	};
+};