Add 'backend/' from commit '040cfd7a75423d4e6136e58a67b40579af4ee966'

git-subtree-dir: backend
git-subtree-mainline: ab911955ed
git-subtree-split: 040cfd7a75

backend/Directory.Build.props

@@ -0,0 +1,9 @@
+<!-- See https://aka.ms/dotnet/msbuild/customize for more details on customizing your build -->
+<Project>
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+</Project>