Add accent colour picker, fix empty user card when accepting friend request, add button to transfer allocations

lib/services/data_service/data_service_traction.dart

@@ -466,6 +466,21 @@ extension DataServiceTraction on DataService {
     }
   }
 
+  Future<void> transferAllocations({
+    required int fromLocoId,
+    required int toLocoId,
+  }) async {
+    try {
+      await api.post('/loco/alloc/transfer', {
+        'loco_id': fromLocoId,
+        'to_loco_id': toLocoId,
+      });
+    } catch (e) {
+      debugPrint('Failed to transfer allocations $fromLocoId -> $toLocoId: $e');
+      rethrow;
+    }
+  }
+
   Future<void> adminDeleteLoco({required int locoId}) async {
     try {
       await api.delete('/loco/admin/delete/$locoId');