feat(migration): Restore sequence_number in workflow_runs

Signed-off-by: -LAN- <laipz8200@outlook.com>

api/migrations/versions/2025_06_19_1633-0ab65e1cc7fa_remove_sequence_number_from_workflow_.py

@@ -28,8 +28,29 @@ def upgrade():
 
 def downgrade():
     # ### commands auto generated by Alembic - please adjust! ###
+
+    # Step 1: Add sequence_number column as nullable first
+    with op.batch_alter_table('workflow_runs', schema=None) as batch_op:
+        batch_op.add_column(sa.Column('sequence_number', sa.INTEGER(), autoincrement=False, nullable=True))
+
+    # Step 2: Populate sequence_number values based on created_at order within each app
+    # This recreates the original sequence numbering logic
+    connection = op.get_bind()
+    connection.execute(sa.text("""
+        UPDATE workflow_runs
+        SET sequence_number = (
+            SELECT ROW_NUMBER() OVER (
+                PARTITION BY tenant_id, app_id
+                ORDER BY created_at, id
+            )
+            FROM workflow_runs wr2
+            WHERE wr2.id = workflow_runs.id
+        )
+    """))
+
+    # Step 3: Make the column NOT NULL and add the index
     with op.batch_alter_table('workflow_runs', schema=None) as batch_op:
-        batch_op.add_column(sa.Column('sequence_number', sa.INTEGER(), autoincrement=False, nullable=False))
+        batch_op.alter_column('sequence_number', nullable=False)
         batch_op.create_index(batch_op.f('workflow_run_tenant_app_sequence_idx'), ['tenant_id', 'app_id', 'sequence_number'], unique=False)
 
     # ### end Alembic commands ###