fix: improve QR code check-in with manual fallback and better error handling

- Add manual check-in buttons for each attendee in the list
- Add manual QR code data input as fallback for camera issues
- Include clerkId in EventAttendee user object for proper check-in
- Improve camera error messages with helpful tips
- Fix TypeScript warnings
- Better UX for organizers with multiple check-in options

server/src/services/eventService.ts

@@ -392,6 +392,7 @@ export const eventService = {
         user: {
           select: {
             id: true,
+            clerkId: true,
             username: true,
             firstName: true,
             lastName: true,