Modernize CMake config

[thomasisensee]

• Replace target_include_directories usage and migrate to target_sources(FILE_SET) for headers
• Require CMake ≥ 3.23
• Use target_compile_features for C++ standard instead of global variables (set(CMAKE_CXX_STANDARD))
• Simplify install rules by using FILE_SET defaults and modern target exports
• Remove CMP0074 policy override (now NEW by default)
• Automatically fetch Catch2 in CI when submodules are not used
• Namespace all CMake targets, build docs and python bindings only when top level project, should solve disable docs, python etc targets when added as a subdirectory #67

The commit a2841d0 also removes the cmake-format pre-commit hook since their output is hard to read and diverges from the CMake documentation style. I think manual formatting is sufficient for CMake files that probably don't change as often as actual code.

[thomasisensee]

I think the token in the GL_API_ACCESS_TOKEN Secret expired. We'd have to save a new valid token.

[thomasisensee]

Actually I'm not sure if I interpret the CMake docs correctly and if CMP0074 should still be set (to NEW).

[Copilot]

Pull request overview

This PR modernizes the CMake configuration to use CMake 3.23+ features, including the FILE_SET mechanism for managing headers, target_compile_features for C++ standard requirements, and improved target exports. The changes also namespace all CMake targets and add support for building docs and Python bindings only when the project is the top-level project, addressing issue #67.

Changes:

• Upgraded minimum CMake version requirement from 3.9 to 3.23 and migrated to modern CMake practices using FILE_SET for headers and target_compile_features for C++ standard
• Namespaced all CMake targets (library, documentation, Python bindings) and made docs/Python bindings conditional on being the top-level project to prevent conflicts when used as a subdirectory
• Simplified CI configurations to automatically fetch Catch2 via FetchContent when submodules are not used, removed manual Catch2 installation steps, and updated dependency versions

Reviewed changes

Copilot reviewed 16 out of 16 changed files in this pull request and generated 10 comments.

Show a summary per file

File	Description
{{cookiecutter.project_slug}}/CMakeLists.txt	Updated to CMake 3.23, replaced CMAKE_CXX_STANDARD with target_compile_features, added PROJECT_IS_TOP_LEVEL checks for app/tests/docs/Python, modernized install rules with FILE_SET
{{cookiecutter.project_slug}}/src/CMakeLists.txt	Migrated to target_sources with FILE_SET HEADERS, replaced target_include_directories with BASE_DIRS/FILES, added target_compile_features
{{cookiecutter.project_slug}}/tests/CMakeLists.txt	Renamed test target with project prefix, improved FetchContent handling for Catch2, added TEST_PREFIX for test discovery
{{cookiecutter.project_slug}}/app/CMakeLists.txt	Modernized to use target_sources pattern
{{cookiecutter.project_slug}}/doc/CMakeLists.txt	Namespaced doxygen and sphinx-doc targets with project prefix, scoped documentation paths
{{cookiecutter.project_slug}}/cmake/{{cookiecutter.project_slug}}Config.cmake.in	Moved from root to cmake/ subdirectory, simplified using @PACKAGE_INIT@ and modern CMake patterns
{{cookiecutter.project_slug}}/{{cookiecutter.project_slug}}Config.cmake.in	Removed old config file from root directory
{{cookiecutter.project_slug}}/.github/workflows/ci.yml	Removed manual Catch2 installation, added Doxygen installation step, updated Python version and option names
{{cookiecutter.project_slug}}/.gitlab-ci.yml	Removed manual Catch2 installation, added Doxygen installation, updated cmake command syntax
{{cookiecutter.project_slug}}/.pre-commit-config.yaml	Removed cmake-format and cmake-lint hooks
{{cookiecutter.project_slug}}/TODO.md	Updated CMake version requirement and config file path references
.github/workflows/ci.yml	Removed manual Catch2 installation, updated Python versions and checkout action
README.md	Updated CMake version requirement and C++ standard support documentation
cookiecutter.json	Bumped Catch2 to 3.12.0 and cibuildwheel to 3.3.1
hooks/post_gen_project.py	Removed conditional removal of old Config.cmake.in file
tests/test_bake_project.py	Updated test targets to use namespaced names

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[lkeegan]

thanks @thomasisensee lgtm! two minor suggestions