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/obj/Debug/net6.0/V2GDecoderNet.GeneratedMSBuildEditorConfig.editorconfig

@@ -0,0 +1,15 @@
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+build_property.EnforceExtendedAnalyzerRules = 
+build_property._SupportedPlatformList = Linux,macOS,Windows
+build_property.RootNamespace = V2GDecoderNet
+build_property.ProjectDir = C:\Data\Source\SIMP\V2GDecoderC\csharp\dotnet\
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