Add devcontainer

Author: hazzik

.devcontainer/devcontainer.json

@@ -0,0 +1,7 @@
+{
+	"name": "C# (.NET)",
+	"image": "mcr.microsoft.com/devcontainers/dotnet:10.0",
+	"features": {
+		"ghcr.io/devcontainers/features/dotnet:2": {}
+	}
+}