Install test

install-test.yml: Install the package and check find_package from a consumer. Pin to a release SHA, as Versioning says.

Input	Type	Default	Description
cmake_version	string	''	CMake version to install (empty = use runner default)
build_type	string	'Release'	CMAKE_BUILD_TYPE for the library build
cmake_args	string	''	Extra CMake configure args for the library (e.g., -DBUILD_TESTING=OFF)
install_prefix	string	'/tmp/install'	CMAKE_INSTALL_PREFIX for the library
consumer_dir	string	''	Path to a consumer CMake project (must have CMakeLists.txt with find_package). Empty = auto-generate a minimal consumer.
package_name	string	''	Package name for find_package() in auto-generated consumer (required if consumer_dir is empty)
target_name	string	''	CMake target to link (e.g., MyLib::MyLib). Defaults to package_name::package_name
header_check	string	''	Header to #include in the consumer test (e.g., mylib/mylib.hpp). Empty = skip header check.
docker_image	string	''	Docker image to run inside (empty = run natively on runner)
source_mount	string	'/workspace/src'	Mount point for source inside Docker container
runner	string	'"ubuntu-latest"'	Runner labels as JSON