Changes:
- L1 transition (4.2): Replaced public on-wire transition header with HTX-tunnelled gateway control stream (CBOR map, replay-safe, token-bucketed). Legacy header prohibited on public networks.
- Path maintenance (4.3): Capped to up to 3 disjoint paths; adaptive probing with explicit back-off limits.
- Outer TLS (5.1): Per-connection auto-calibration to the front...