blip25-codec

MBE codec engine: IMBE (P25 Phase 1) + AMBE+2 (P25 Phase 2), encode and decode. Wire layers are spec-derived from TIA-102.BABA; the shared analysis/synthesis core both codecs' audio comes from was recovered by reverse engineering the reference's software vocoder and reproduced bit-for-bit. See ATTRIBUTION.md and PATENT_NOTICE.md in the repository. Implementation detail of `blip25-mbe` — use that crate's `Vocoder` instead of depending on this directly.