Provide CMake integration and cross-platform native artifacts

[GeneralPawz]

What

Provide a supported way for a C or C++ project to build or consume the Axiolid C ABI with CMake. Package the generated header and native library as an imported target without leaking workspace layout, Cargo internals, or global compiler settings into the consumer.

Why now

A C ABI that only builds from inside the Rust workspace is not an integration surface. Native downstreams need deterministic discovery, linking, installation, runtime-library handling, and a version compatibility check on every supported platform.

Definition of done

• find_package(Axiolid CONFIG REQUIRED) exposes a namespaced imported target and documented ABI version.
• A minimal out-of-tree C project and C++ project both configure, build, link, and run.
• Source-build and packaged-artifact paths pin an immutable release and produce equivalent behavior.
• Linux, macOS, and Windows CI covers supported static/shared and runtime-library choices.
• Install layout, transitive system libraries, rpath/DLL placement, debug/release selection, and cross-compilation behavior are explicit.
• Builds do not use host-specific target-cpu=native defaults or mutate consumer-global CMake flags.
• Artifact checksums, license material, and provenance are emitted by the release flow.

Non-goals

Application-specific CMake plugins belong in their downstream repositories.

Area

release

Effort

High