Need to an option in the model to allow timestamps

Currently we manually add the filed created_at and updated_at. Let's add it automatically by just setting settings in the model.

Start in the PHP model(s) that define expense/budget records, where created_at and updated_at are being handled manually. Check related schema/migration files to confirm those columns exist, then inspect the model configuration section for a timestamp option. No tests or files are named in the issue, so validate by following the normal create/update model flow and confirming timestamps are filled automatically without manual assignment.

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