Fix: remove updated_at from user_tenants INSERT in migration 0037

alembic/versions/0037_user_tenant_model.py

@@ -83,7 +83,7 @@ def upgrade() -> None:
     # ── 5. Data migration: copy tenant_id, role, role_id from users to user_tenants ─
     # Only create UserTenant rows that don't already exist
     conn.execute(sa.text("""
-        INSERT INTO user_tenants (user_id, tenant_id, is_default, role, role_id, status, created_at, updated_at)
+        INSERT INTO user_tenants (user_id, tenant_id, is_default, role, role_id, status, created_at)
         SELECT 
             u.id, 
             u.tenant_id, 
@@ -91,7 +91,6 @@ def upgrade() -> None:
             COALESCE(u.role, 'viewer'), 
             u.role_id,
             'active',
-            NOW(), 
             NOW()
         FROM users u
         WHERE NOT EXISTS (