Verification & Reproducibility Baseline.
Includes:
- stable verify --json schema;
- centralized and documented exit codes;
- MBN byte-level documentation and golden vectors;
- num_v1 bitstream-pinned test vectors;
- deterministic P2 benchmark/repro harness;
- benchmark and reproducibility documentation.
Non-goals:
- no performance claim such as beating zstd/zlib;
- no large framework/plugin refactor;
- no silent format migration.