fix(gateway): preserve kanban notifier chat type

gateway/kanban_watchers.py

@@ -631,27 +631,24 @@ class GatewayKanbanWatchersMixin:
                             try:
                                 from gateway.session import SessionSource
                                 from gateway.wake import deliver_wake
-                                # KNOWN LIMITATION (tracked follow-up): the
-                                # subscription row does not persist the
-                                # creator's chat_type, and it is not carried
-                                # on the session-context bridge, so we cannot
-                                # faithfully reconstruct the creator's real
-                                # session key here. build_session_key() keys
-                                # DMs (":dm:<chat_id>") on a wholly different
-                                # shape from group/thread, so any hardcoded
-                                # value mis-routes some creators. "group" is
-                                # the least-surprising default for the
-                                # dashboard/group flows this wake primarily
-                                # serves; DM-originated creators are handled
-                                # by the follow-up that stamps + persists
-                                # chat_type end-to-end. handle_message()
-                                # get_or_create_session's the target, so a
-                                # mismatch degrades to "wake lands in a fresh
-                                # group session" — never an exception.
+                                # Rebuild the creator's real session scope from
+                                # the chat_type persisted on the subscription
+                                # row (#56580). build_session_key() keys DMs
+                                # (":dm:<chat_id>") on a wholly different shape
+                                # from group/thread, so the old hardcoded
+                                # "group" mis-routed DM/thread creators into a
+                                # fresh session. Legacy rows written before the
+                                # column existed store NULL/'' — fall back to
+                                # "group" for them (the historical default that
+                                # suits the dashboard/group flows).
+                                # handle_message() get_or_create_session's the
+                                # target, so a mismatch only ever degrades to a
+                                # fresh session, never an exception.
+                                _chat_type = str(sub.get("chat_type") or "").strip() or "group"
                                 _source = SessionSource(
                                     platform=plat,
                                     chat_id=sub["chat_id"],
-                                    chat_type="group",
+                                    chat_type=_chat_type,
                                     thread_id=sub.get("thread_id") or None,
                                     user_id=sub.get("user_id"),
                                     profile=sub_profile or None,