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/date-fns/parse/_lib/parsers/ISOWeekParser.js

@@ -0,0 +1,47 @@
+import { setISOWeek } from "../../../setISOWeek.js";
+import { startOfISOWeek } from "../../../startOfISOWeek.js";
+import { numericPatterns } from "../constants.js";
+import { Parser } from "../Parser.js";
+
+import { parseNDigits, parseNumericPattern } from "../utils.js";
+
+// ISO week of year
+export class ISOWeekParser extends Parser {
+  priority = 100;
+
+  parse(dateString, token, match) {
+    switch (token) {
+      case "I":
+        return parseNumericPattern(numericPatterns.week, dateString);
+      case "Io":
+        return match.ordinalNumber(dateString, { unit: "week" });
+      default:
+        return parseNDigits(token.length, dateString);
+    }
+  }
+
+  validate(_date, value) {
+    return value >= 1 && value <= 53;
+  }
+
+  set(date, _flags, value) {
+    return startOfISOWeek(setISOWeek(date, value));
+  }
+
+  incompatibleTokens = [
+    "y",
+    "Y",
+    "u",
+    "q",
+    "Q",
+    "M",
+    "L",
+    "w",
+    "d",
+    "D",
+    "e",
+    "c",
+    "t",
+    "T",
+  ];
+}