feat: ADRF async views (phase1) + native async serializers (phase2) + async cache infra

tool/views/text_diff_view.py

@@ -1,6 +1,6 @@
 import difflib
 from rest_framework.decorators import permission_classes
-from rest_framework.views import APIView
+from adrf.views import APIView
 from rest_framework.response import Response
 from rest_framework import status
 from rest_framework.permissions import AllowAny