Add Parts COGS to report

Right now, AIO reports merge Parts and Products into one line for both COGS and Revenue. This makes it hard to see the true profitability of service parts compared to finished products.

We need the reports to break these out separately so we can analyze margins, costs, and revenue performance more accurately. For example, seeing “Parts Revenue” and “Product Revenue” as distinct lines would give us much clearer insights.

Historical reports can stay as they are, but going forward, the Income Statement and Balance Sheet should reflect this new split.