build: use ASP.NET runtime for backend images

packaging/container/Backend.Containerfile

@@ -1,4 +1,4 @@
-FROM mcr.microsoft.com/dotnet/runtime-deps:10.0-noble-chiseled-extra
+FROM mcr.microsoft.com/dotnet/aspnet:10.0-noble-chiseled-extra
 
 ARG APP_VERSION=unknown
 LABEL org.opencontainers.image.title="Monitor Backend" \
@@ -17,4 +17,4 @@ ENV ASPNETCORE_HTTP_PORTS=8080 \
 USER 1654:1654
 VOLUME ["/data"]
 EXPOSE 8080
-ENTRYPOINT ["/app/monitor-backend"]
+ENTRYPOINT ["dotnet", "/app/monitor-backend.dll"]