iOS: Don't fall off the end of checkPermission

The switch covered every AVAuthorizationStatus known today, so an unhandled one
would return garbage from a non-void function. Treat unknown statuses as denied.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01JZk5y4Fzw811WJoNWZb8Sc

ios/CameraHelper.mm

@@ -53,6 +53,10 @@ NSString *getSelectedCamera() {
         case AVAuthorizationStatusAuthorized: {
             return 0;
         }
+        default: {
+            NSLog(@"unknown camera authorization status %ld, treating as denied", (long)status);
+            return 1;
+        }
     }
 }