Move the multithreaded compressStream2 outer coordinator into the Rust compression module. The C bridge now owns only the private ZSTDMT call and consumed/produced counters, while Rust preserves the progress loop, completion ordering, and error handoff.
Keep the MT context mutations, diagnostics, assertions, and buffer-expectation publication in C because they depend on the private context layout. Add callback-driven tests for continue/break, error completion, end trace/reset ordering, and malformed states.
Test Plan:
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo +nightly fmt --manifest-path rust/Cargo.toml --all -- --check
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo clippy --manifest-path rust/Cargo.toml --all-targets -- -D warnings
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 make -j1
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo test --manifest-path rust/cli/Cargo.toml --all-targets
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 make -j1 -C tests test
- ulimit -v 41943040; CARGO_BUILD_JOBS=1 cargo clippy --manifest-path rust/cli/Cargo.toml --all-targets -- -D warnings