Reworked GitLab CI to support branch-aware OS checks (all supported OS on main, Ubuntu 24.04 on feature branches), restored explicit lint/sanitize/coverage/tests/docs stages, and unified Docker image naming to $DOCKER_URL/$IMAGE_OS_SUFFIX/{ci,dev}:$DOCKER_CI_TAG with per-OS image publishing. Improved documentation generation by adding multi-language output layout (build/docs//), LLVM+doxygen+m.css flow with HTML/XML/LaTeX/PDF outputs, automatic Graphviz dot detection in CMake, and updated setup scripts/docs for required LaTeX and cross-platform dependencies.