feat: Complete cross-platform build system and folder reorganization

- Reorganize project structure: Port/ → DotNet/, VC/, C++/
- Add comprehensive cross-platform build automation
  - Windows: build_all.bat, build.bat files for all components
  - Linux/macOS: build_all.sh, build.sh files for all components
- Update all build scripts with correct folder paths
- Create test automation scripts (test_all.bat/sh)
- Update documentation to reflect new structure
- Maintain 100% roundtrip accuracy for test5.exi (pure EXI)
- Support both Windows MSBuild and Linux GCC compilation

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

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

VC/build.bat

@@ -0,0 +1,29 @@
+@echo off
+echo Building V2GDecoder VC++ Project...
+
+REM Check if Visual Studio 2022 is installed (Professional or Community)
+set MSBUILD_PRO="C:\Program Files\Microsoft Visual Studio\2022\Professional\MSBuild\Current\Bin\MSBuild.exe"
+set MSBUILD_COM="C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\MSBuild.exe"
+set MSBUILD_BT="F:\(VHD) Program Files\Microsoft Visual Studio\2022\MSBuild\Current\Bin\MSBuild.exe"
+
+if exist %MSBUILD_PRO% (
+    echo "Found Visual Studio 2022 Professional"
+    set MSBUILD=%MSBUILD_PRO%
+) else if exist %MSBUILD_COM% (
+    echo "Found Visual Studio 2022 Community"
+    set MSBUILD=%MSBUILD_COM%
+) else if exist %MSBUILD_BT% (
+    echo "Found Visual Studio 2022 BuildTools"
+    set MSBUILD=%MSBUILD_BT%
+) else (
+    echo "Visual Studio 2022 (Professional or Community) not found!"
+    echo "Please install Visual Studio 2022 or update the MSBuild path."
+    pause
+    exit /b 1
+)
+
+REM Build Debug x64 configuration
+echo Building Debug x64 configuration...
+%MSBUILD% V2GDecoderC.sln -property:Configuration=Debug -property:Platform=x64 -verbosity:normal
+
+pause