Use hub 'name' in routes & add top-post sorting

Switch hub endpoints to use the hub `name` slug and update frontend routes/clients accordingly. Backend: HubViewSet now uses lookup_field='name'; PostViewSet list supports `sort=top` with vote_score annotation and time windows/custom ranges, and a new TopPostsCursorPagination was added. Frontend: routes changed from `/hub/:id` to `/h/:name`, the generated hubs API was updated from id->name, and the hub feed client accepts `sort`, `time`, `start`, and `end` params (query key updated). Also adds new homepage UI components (HeroSection, DroneSection) and navbar improvements (scroll state, auto-close mobile menu on route changes, and small icon/class tweaks).

backend/social/hubs/views.py

@@ -58,6 +58,7 @@ from .serializers import HubPermissionSerializer, HubSerializer, TagsSerializer,
 class HubViewSet(viewsets.ModelViewSet):
     serializer_class = HubSerializer
     permission_classes = [CanEditHub]
+    lookup_field = 'name'
     filterset_fields = ['is_public', 'owner']
     search_fields = ['name', 'description']
     ordering_fields = ['name']