feat: auto-register walk-in attendees during check-in

- Automatically register users who scan QR code but aren't pre-registered
- Mark walk-in registrations with wasWalkIn flag
- Show different success messages for walk-ins vs pre-registered attendees
- Check in walk-ins immediately upon registration
- Remove 'not registered' error - now handles walk-ins gracefully
- Update both QR scan and manual check-in to support walk-ins

src/pages/EventCheckInPage.tsx

@@ -55,7 +55,13 @@ export function EventCheckInPage() {
 
     try {
       // Send the Clerk ID to backend and let it handle the lookup
-      const response = await apiClient.post<{ success: boolean; username?: string; firstName?: string; lastName?: string }>(
+      const response = await apiClient.post<{ 
+        success: boolean; 
+        username?: string; 
+        firstName?: string; 
+        lastName?: string;
+        wasWalkIn?: boolean;
+      }>(
         `/events/${eventId}/checkin`,
         { clerkUserId }
       );
@@ -64,7 +70,11 @@ export function EventCheckInPage() {
         ? `${response.firstName} ${response.lastName}`
         : response.username || 'user';
       
-      setSuccessMessage(`Successfully checked in ${displayName}`);
+      if (response.wasWalkIn) {
+        setSuccessMessage(`✨ ${displayName} registered and checked in as walk-in!`);
+      } else {
+        setSuccessMessage(`✓ Successfully checked in ${displayName}`);
+      }
 
       // Reload attendees to get updated status
       setTimeout(() => {
@@ -255,7 +265,13 @@ export function EventCheckInPage() {
                     <button
                       onClick={async () => {
                         try {
-                          const response = await apiClient.post<{ success: boolean; username?: string; firstName?: string; lastName?: string }>(
+                          const response = await apiClient.post<{ 
+                            success: boolean; 
+                            username?: string; 
+                            firstName?: string; 
+                            lastName?: string;
+                            wasWalkIn?: boolean;
+                          }>(
                             `/events/${eventId}/checkin`,
                             { clerkUserId: attendee.user.clerkId }
                           );
@@ -264,7 +280,11 @@ export function EventCheckInPage() {
                             ? `${response.firstName} ${response.lastName}`
                             : response.username || attendee.user.username;
                           
-                          setSuccessMessage(`Successfully checked in ${displayName}`);
+                          if (response.wasWalkIn) {
+                            setSuccessMessage(`✨ ${displayName} registered and checked in as walk-in!`);
+                          } else {
+                            setSuccessMessage(`✓ Successfully checked in ${displayName}`);
+                          }
                           
                           // Reload attendees to get updated status
                           setTimeout(() => {

src/pages/UserProfilePage.tsx

@@ -98,7 +98,9 @@ export function UserProfilePage() {
         areasOfInterest: profileData.areasOfInterest || [],
       });
     } catch (err) {
-      setError(err instanceof Error ? err.message : 'Failed to load profile');
+      console.error('Error loading profile data:', err);
+      const errorMessage = err instanceof Error ? err.message : 'Failed to load profile';
+      setError(errorMessage);
     } finally {
       setLoading(false);
     }