Build initial SabTrace C++ log analyser

[Saboreq]

What changed

• adds a modern C++20 command-line log analyser with no runtime dependencies
• supports files and standard input, literal search, ECMAScript regex, level filtering, case-insensitive matching, result limits, color control, statistics, and JSON reports
• detects TRACE, DEBUG, INFO, WARN, ERROR, FATAL, and UNKNOWN lines
• adds dependency-free unit tests and a sample log
• adds CMake build/install configuration and development/release presets
• adds CI for GCC on Linux, MSVC on Windows, and Clang on macOS
• adds a tagged release workflow that packages platform binaries and publishes SHA-256 checksums
• adds a professional README, changelog, contributing guide, MIT license, and formatting configuration

CLI behavior

Exit codes follow a script-friendly convention:

• 0: completed with one or more matches
• 1: completed successfully with no matches
• 2: invalid arguments, invalid regex, or input/output failure

Validation

Local Linux validation completed successfully:

cmake --preset release
cmake --build --preset release --parallel
ctest --preset release

All tests passed with GCC 14.2 and the sample log/JSON export were smoke-tested. GitHub Actions will provide the cross-platform validation before merge.

Release usage

After merge, pushing a semantic version tag such as v0.1.0 will build archives for Windows, Linux, and macOS and publish a GitHub Release with checksums.