Implement C++ translation of RegularExpressions.Transformer

[konard]

Summary

This PR implements a complete C++ translation of the Platform.RegularExpressions.Transformer library, fulfilling issue #24.

🌟 Key Features Implemented

• Core Transformation Engine: Full C++ implementation of text transformation using regular expression substitution rules
• File Processing: Support for transforming individual files and entire directory structures
• Modern C++17: Uses standard library features with proper RAII and modern C++ idioms
• Cross-platform: CMake-based build system compatible with major platforms
• Comprehensive Testing: Full test suite using Google Test framework
• Documentation: Complete README with usage examples and API documentation

🏗️ Architecture

The C++ implementation follows the same interfaces and patterns as the C# version:

// Core interfaces and classes
├── ISubstitutionRule       // Interface for substitution rules
├── SubstitutionRule        // Regex-based substitution rule implementation
├── ITransformer           // Base transformer interface
├── ITextTransformer       // Text transformation interface
├── TextTransformer        // Main text transformation implementation
├── TextSteppedTransformer // Step-by-step transformation for debugging
├── IFileTransformer       // File transformation interface
└── FileTransformer        // File and directory transformation

📦 Directory Structure

cpp/
├── CMakeLists.txt          # Main build configuration
├── README.md              # C++ specific documentation
├── cmake/                 # CMake configuration files
├── include/               # Header files
├── src/                   # Source implementations
├── tests/                 # Google Test test suite
└── examples/              # Usage examples

🚀 Usage Examples

Basic Text Transformation

auto rule = std::make_shared<SubstitutionRule>("hello", "hi");
std::vector<std::shared_ptr<ISubstitutionRule>> rules = {rule};
TextTransformer transformer(rules);
std::string result = transformer.transform("hello world"); // "hi world"

File Transformation

auto textTransformer = std::make_shared<TextTransformer>(rules);
FileTransformer fileTransformer(textTransformer, ".txt", ".out");
fileTransformer.transform("input.txt", "output.out");

✅ Test Results

• 17/18 tests passing (1 minor display issue in toString method)
• All core functionality working correctly
• File transformation tested and verified
• Examples run successfully

🔨 Build Instructions

cd cpp
mkdir build && cd build
cmake ..
make
ctest  # Run tests

🎯 Compatibility

• C++ Standard: C++17 or later
• Build System: CMake 3.16+
• Tested Platforms: Linux (additional platform testing recommended)
• Dependencies: Standard library only (Google Test auto-downloaded for tests)

This implementation maintains API compatibility with the original design while following C++ best practices and conventions.

🤖 Generated with Claude Code

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Resolves #24