- [x] Add versioned gateway and authority definitions to the schema and tunnel descriptor.
- [x] Add registered media/audio/sequenced-input flow identifiers and positive/negative fixtures.
- [x] Regenerate Go/Rust/Swift bindings and descriptor outputs.
- [x] Run strict validation, cross-language conformance, and deterministic fixture hashing.
- [ ] Freeze the local Protocol candidate commit and record its hash for consumers.