Add a Dependency

1. Check the license - only permissive licenses are allowed: MIT, BSD, zlib, Apache 2.0, public domain or CC0. Anything else needs the user's decision first (see AGENTS.md). Check docs/TechStack.md#libraries - the library may already be planned, with a chosen version policy.
2. Pick an exact version - a release tag, or a specific commit when releases are stale (as for sol2). Never a branch.
3. Hash the archive - download the release archive (GitHub: https://github.com/<owner>/<repo>/archive/refs/tags/<tag>.tar.gz, or .../archive/<commit>.tar.gz) into an empty scratch directory, and compute its SHA256 (sha256sum, or Get-FileHash on Windows). If the project publishes checksums, compare against them.
4. Declare it in cmake/Dependencies.cmake:

   # <name> - <what it's for> (<license>)
   ls_declare_dependency(<name>
       URL <archive URL>
       SHA256 <hash>
   )
   set(<OPTION> <value> CACHE BOOL "" FORCE)   # turn off the dependency's tests, examples and install rules
   

   and add it to FetchContent_MakeAvailable(). If it has no CMake build, define its target after FetchContent_MakeAvailable(), as Lua's is.
5. Respect the layering - link it only to the targets that need it. LodestoneCore must never link GLFW, nvrhi, miniaudio or anything that needs a window, GPU or audio device (docs/Architecture.md#targets-and-layering).
6. Document it - add the library, version, license, purpose and whether it ships in exported games to THIRD_PARTY_LICENSES.md, with the full license text from the archive. Add it to docs/TechStack.md#libraries if it isn't listed.
7. Test it - build every configuration on your platform and run the tests (build-and-test skill). CI checks the other platforms. If the library throws exceptions, catch them where Lodestone calls it and return std::expected errors (docs/CodeStyle.md#error-handling).