Add .NET 8.0 C# port of OpenV2G EXI codec

- Port core EXI encoding/decoding functionality to C#
- Implement V2G protocol parsing and analysis
- Add simplified decoder/encoder for roundtrip testing
- Create comprehensive error handling with EXI exceptions
- Support both byte array and file stream operations
- Include packet structure analysis for V2GTP data
- Successfully builds and runs basic functionality tests

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

csharp/dotnet/bin/Debug/net8.0/V2GDecoderNet.runtimeconfig.json

@@ -0,0 +1,12 @@
+{
+  "runtimeOptions": {
+    "tfm": "net8.0",
+    "framework": {
+      "name": "Microsoft.NETCore.App",
+      "version": "8.0.0"
+    },
+    "configProperties": {
+      "System.Runtime.Serialization.EnableUnsafeBinaryFormatterSerialization": false
+    }
+  }
+}