feat(ci): add Dagger CI pipeline with Python SDK
- Add dagger.json and .dagger/ module with Python SDK
- CI pipeline: base, build, test, ci, doc functions
- Uses ocaml/opam:debian-12-ocaml-5.4 image
- Add missing deps to dune-project: kcas_data, climate
- Reports to Dagger Cloud, works with Podman