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/escalade/dist/index.js

@@ -0,0 +1,22 @@
+const { dirname, resolve } = require('path');
+const { readdir, stat } = require('fs');
+const { promisify } = require('util');
+
+const toStats = promisify(stat);
+const toRead = promisify(readdir);
+
+module.exports = async function (start, callback) {
+	let dir = resolve('.', start);
+	let tmp, stats = await toStats(dir);
+
+	if (!stats.isDirectory()) {
+		dir = dirname(dir);
+	}
+
+	while (true) {
+		tmp = await callback(dir, await toRead(dir));
+		if (tmp) return resolve(dir, tmp);
+		dir = dirname(tmp = dir);
+		if (tmp === dir) break;
+	}
+}

frontend/node_modules/escalade/dist/index.mjs

@@ -0,0 +1,22 @@
+import { dirname, resolve } from 'path';
+import { readdir, stat } from 'fs';
+import { promisify } from 'util';
+
+const toStats = promisify(stat);
+const toRead = promisify(readdir);
+
+export default async function (start, callback) {
+	let dir = resolve('.', start);
+	let tmp, stats = await toStats(dir);
+
+	if (!stats.isDirectory()) {
+		dir = dirname(dir);
+	}
+
+	while (true) {
+		tmp = await callback(dir, await toRead(dir));
+		if (tmp) return resolve(dir, tmp);
+		dir = dirname(tmp = dir);
+		if (tmp === dir) break;
+	}
+}