feat: add API endpoint to get devices list

server/backend/services/devices_service.py

@@ -0,0 +1,10 @@
+from domain.entities import Device
+from adapters.postgres.device_repository import DeviceRepository
+
+
+class DeviceService:
+    def __init__(self, device_repo: DeviceRepository) -> None:
+        self._device_repo = device_repo
+
+    def get_all_devices(self) -> list[Device]:
+        return self._device_repo.get_all()