Keep validation of the applied compression parameters in C and delegate the context-free minimum calculation through a narrow ABI leaf. Preserve the public getter and deprecated block-compression paths.
Test Plan:
- cargo test --manifest-path rust/Cargo.toml --no-default-features --features compression
- cargo clippy --manifest-path rust/Cargo.toml --no-default-features --features compression --all-targets
- cargo +nightly fmt --manifest-path rust/Cargo.toml
- make -B -C lib -j2 lib
- make -C tests -j2 fuzzer
- tests/fuzzer -s4560 -t47 -i48 -v