Summary by CodeRabbit

• New Features

  • Full pure‑Rust LZMA stack (encoders/decoders, LZMA2/LZIP, block/stream/index handling), filter support (delta/BCJ), VLI utilities, CRC32/CRC64/SHA256 checks, microlzma path, outqueue, and multithreaded stream/block encoders/decoders.
  • One‑shot and streaming buffer encode/decode APIs and a benchmark suite comparing Rust vs C backends.

• Documentation

  • Added governance and migration guidance document.

• Chores

  • Workspace and manifest updates, feature/flag rework, dev/bench dependencies and CI MSRV bumped to Rust 1.63.