feat(conversations): the recall hook and the user sink learn whose turn it is

src/beaver_gateway/conversations/turns.py

@@ -336,9 +336,11 @@ class Turns(Seeds):
         if self._envelope is None:
             return None
         if conv.kind == "master":
-            return self._envelope.build(text=text, kind="master")
+            return self._envelope.build(text=text, kind="master", agent=conv.agent_name)
         if conv.kind == "branch":
-            return self._envelope.recall_only(text=text, kind="branch")
+            return self._envelope.recall_only(
+                text=text, kind="branch", agent=conv.agent_name
+            )
         return None
 
     async def _note_user(self, conv: Conversation, text: str) -> None:
@@ -350,6 +352,7 @@ class Turns(Seeds):
             title=conv.title,
             text=text,
             at=datetime.now(UTC),
+            agent=conv.agent_name,
         )
         try:
             result = self._user_sink(message)