👷 ci: run spore CLI setup with Python 3.13

[zrr1999]

Summary

• Add explicit Python 3.13 setup to the uv-based Spore CLI CI job before installing spore-lang.

Validation

• uvx --python 3.13 prek run --all-files
• cargo build --manifest-path host/Cargo.toml
• cargo test --manifest-path host/Cargo.toml
• uvx --python 3.13 --from spore-lang==0.0.3 spore --version
• uvx --python 3.13 --from spore-lang==0.0.3 spore format --check
• find src/basic_cli -name '*.sp' -type f | sort | xargs -n 1 uvx --python 3.13 --from spore-lang==0.0.3 spore check
• uvx --python 3.13 --from spore-lang==0.0.3 spore check examples/hello.sp
• uvx --python 3.13 --from spore-lang==0.0.3 spore check examples/hello-app/src/main.sp
• find src/basic_cli -name '*.sp' -type f | sort | xargs -n 1 uvx --python 3.13 --from spore-lang==0.0.3 spore build
• uvx --python 3.13 --from spore-lang==0.0.3 spore run examples/hello.sp
• (cd examples/hello-app && uvx --python 3.13 --from spore-lang==0.0.3 spore run src/main.sp)
• uvx --python 3.13 --from spore-lang==0.0.3 spore test
• git diff --check

Notes

• No blockers.