feat(postbox): schedule lifecycle notification reconciliation

src/govoplan_core/core/postbox.py

@@ -309,6 +309,7 @@ class PostboxDeliveryRequest:
     body_text: str | None = None
     sender_label: str | None = None
     classification: str = "internal"
+    action_required: bool = False
     participants: tuple[PostboxParticipantRef, ...] = ()
     attachments: tuple[PostboxAttachmentRef, ...] = ()
     expires_at: datetime | None = None
@@ -511,6 +512,17 @@ class PostboxRoutingProvider(Protocol):
     ) -> Mapping[str, object]:
         ...
 
+    def reconcile_notification_lifecycle(
+        self,
+        session: object,
+        *,
+        tenant_id: str | None = None,
+        limit: int = 50,
+    ) -> Mapping[str, object]:
+        """Reconcile assignment-derived Postbox notification facts."""
+
+        ...
+
 
 @runtime_checkable
 class PostboxPortalProjectionProvider(Protocol):