refacto: rename app into backend, to prepare for frontend dev

server/backend/ports/reading_query_repository.py

@@ -0,0 +1,16 @@
+from abc import ABC, abstractmethod
+from datetime import datetime
+
+from domain.value_objects import Granularity
+from domain.entities import ConsumptionPoint
+
+class ReadingQueryRepository(ABC):
+    @abstractmethod
+    def get_consumption(
+        self,
+        dev_eui: str,
+        start: datetime,
+        end: datetime,
+        granularity: Granularity,
+    ) -> list[ConsumptionPoint]:
+        ...