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

src/beaver_gateway/conversations/envelope.py

@@ -25,6 +25,8 @@ class RecallContext:
     text: str
     kind: str
     now: datetime
+    agent: str = ""
+    """Agent whose turn it is; a setup with several tells them apart by it."""
 
 
 @dataclass(slots=True)
@@ -40,7 +42,12 @@ class Envelope:
     texts: EnvelopeTexts = field(default_factory=EnvelopeTexts)
 
     def build(
-        self, *, now: datetime | None = None, text: str = "", kind: str = "master"
+        self,
+        *,
+        now: datetime | None = None,
+        text: str = "",
+        kind: str = "master",
+        agent: str = "",
     ) -> str:
         now = now or datetime.now(UTC)
         changes = self.watch.take() if self.watch is not None else []
@@ -59,20 +66,26 @@ class Envelope:
             texts=self.texts,
         )
         self.last_at = now
-        block = self.recall_block(text=text, kind=kind, now=now)
+        block = self.recall_block(text=text, kind=kind, now=now, agent=agent)
         return f"{out}\n{block}" if block else out
 
     def recall_only(
-        self, *, text: str, kind: str, now: datetime | None = None
+        self, *, text: str, kind: str, now: datetime | None = None, agent: str = ""
     ) -> str | None:
-        block = self.recall_block(text=text, kind=kind, now=now or datetime.now(UTC))
+        block = self.recall_block(
+            text=text, kind=kind, now=now or datetime.now(UTC), agent=agent
+        )
         return f"{self.texts.header}\n{block}" if block else None
 
-    def recall_block(self, *, text: str, kind: str, now: datetime) -> str | None:
+    def recall_block(
+        self, *, text: str, kind: str, now: datetime, agent: str = ""
+    ) -> str | None:
         if self.recall is None or not text.strip():
             return None
         try:
-            block = self.recall(RecallContext(text=text, kind=kind, now=now))
+            block = self.recall(
+                RecallContext(text=text, kind=kind, now=now, agent=agent)
+            )
         except Exception:  # noqa: BLE001
             _log.exception("recall hook failed")
             return None