The connector stamps `profile` on inbound and passthrough_forward frames but the
gateway never sent it back, so the connector had nothing to stamp on the NEXT
interaction of a routed chat. `_capture_scope` now remembers the routed profile
per chat, `_with_scope` echoes it as `metadata.profile` on chat-addressed frames,
and `send_follow_up` derives it from the `agent:<profile>:` key namespace. A
single-profile gateway emits no key — frames stay byte-identical. Contract §4
documents the round-trip.
e09cd0d2bc