`[2026-06-19]` **op-feed handshake field-name fix (#17, `v0.17.17` `d60b77d`): `capabilities_requested`→`capabilities`.** The summary read a field that never exists on the wire (bifrost reads `capabilities`, `_protocol.py:181`) → caps_requested was always null. Surfaced by the heid panel (Regin) during the D1 review — a latent #17 bug, not D1 drift.
