new is_agentic flag for chatmessages (#4026)

* new is_agentic flag for chatmessages

* added cancelled error to db

* added cancelled error to returned message

backend/alembic/versions/9c00a2bccb83_chat_message_agentic.py

@@ -0,0 +1,43 @@
+"""chat_message_agentic
+
+Revision ID: 9c00a2bccb83
+Revises: b7a7eee5aa15
+Create Date: 2025-02-17 11:15:43.081150
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "9c00a2bccb83"
+down_revision = "b7a7eee5aa15"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    # First add the column as nullable
+    op.add_column("chat_message", sa.Column("is_agentic", sa.Boolean(), nullable=True))
+
+    # Update existing rows based on presence of SubQuestions
+    op.execute(
+        """
+        UPDATE chat_message
+        SET is_agentic = EXISTS (
+            SELECT 1
+            FROM agent__sub_question
+            WHERE agent__sub_question.primary_question_id = chat_message.id
+        )
+        WHERE is_agentic IS NULL
+    """
+    )
+
+    # Make the column non-nullable with a default value of False
+    op.alter_column(
+        "chat_message", "is_agentic", nullable=False, server_default=sa.text("false")
+    )
+
+
+def downgrade() -> None:
+    op.drop_column("chat_message", "is_agentic")