fix(chat): allow administrator to delete channel-only sessions

Align administrator session deletion with the administrator chat view so
sessions surfaced through channel_session_v2 can be removed without a
ui_session_owner row.

Co-authored-by: Cursor <cursoragent@cursor.com>

svc/persistence/assistant_store_protocol.py

@@ -60,6 +60,7 @@ class AssistantStoreProtocol(Protocol):
     def delete_memory_item(self, *, memory_id: 'str') -> 'int': ...
     def delete_message(self, *, session_id: 'str', message_id: 'int') -> 'bool': ...
     def delete_session(self, session_id: 'str') -> 'None': ...
+    def delete_session_for_administrator_chat_view(self, *, session_id: 'str', username: 'str', tenant_id: 'str') -> 'bool': ...
     def delete_session_for_user(self, *, session_id: 'str', tenant_id: 'str', user_id: 'str') -> 'bool': ...
     def delete_session_in_tenant(self, *, session_id: 'str', tenant_id: 'str') -> 'bool': ...
     def delete_setting(self, key: 'str') -> 'None': ...

svc/persistence/sa_repos/chat_sessions.py

@@ -614,6 +614,31 @@ class ChatSessionsSaRepository:
             conn.execute(delete(chat_session).where(chat_session.c.id == sid))
         return True
 
+    def try_delete_chat_session_for_administrator_chat_view(
+        self, *, session_id: str, username: str, tenant_id: str
+    ) -> bool:
+        sid = str(session_id or "").strip()
+        if not sid:
+            return False
+        ids = self._administrator_chat_session_ids_subquery(
+            username=username,
+            tenant_id=tenant_id,
+        )
+        with self._engine.begin() as conn:
+            chk = conn.execute(
+                select(1)
+                .select_from(chat_session)
+                .where(
+                    chat_session.c.id == sid,
+                    chat_session.c.id.in_(select(ids.c.sid)),
+                )
+                .limit(1)
+            ).first()
+            if not chk:
+                return False
+            conn.execute(delete(chat_session).where(chat_session.c.id == sid))
+        return True
+
     def try_delete_chat_session_for_tenant(self, *, session_id: str, tenant_id: str) -> bool:
         sid, tid = str(session_id or "").strip(), str(tenant_id)
         if not sid:

svc/persistence/sqlite_store.py

@@ -1666,6 +1666,15 @@ class SqliteStore(ScheduledJobStoreMixin):
             session_id=session_id, username=username, tenant_id=tenant_id
         )
 
+    def delete_session_for_administrator_chat_view(
+        self, *, session_id: str, username: str, tenant_id: str
+    ) -> bool:
+        return self._chat_sessions_repo().try_delete_chat_session_for_administrator_chat_view(
+            session_id=session_id,
+            username=username,
+            tenant_id=tenant_id,
+        )
+
     def get_session_for_administrator_username(
         self, *, session_id: str, username: str
     ) -> Optional[ChatSession]: