* Fix#690: Apply clang-format consistently with CI
Applied clang-format-19 to all source files to enforce consistent
formatting according to the existing .clang-format configuration.
Added auto-clang-format GitHub Actions workflow (from
cpp-best-practices/cmake_template) that runs on pull requests to
automatically format and commit any style violations going forward.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
