Fix linting errors and Synology rootUrl issue

src/lib/calendar-events.ts

@@ -703,7 +703,7 @@ export const createCalendarEvent = async (
     // Handle all-day event normalization for Apple (requires 'date' property, not 'dateTime')
     // AND exclusive end date (add 1 day if needed)
     const start = { ...event.start! };
-    let end = { ...event.end! };
+    const end = { ...event.end! };
 
     if (event.allDay) {
       if (start.dateTime && !start.date) {

src/lib/synology-calendar.ts

@@ -72,6 +72,7 @@ const loginClient = async (client: DAVClient, serverUrl: string, username: strin
         serverUrl: client.serverUrl,
         accountType: 'caldav',
         homeUrl,
+        rootUrl: homeUrl, // tsdav requires rootUrl for fetchCalendars
       };
     } else {
       throw err;