v1.2.7 POS Refunds

POS transaction history now supports item refunds, including partial quantities. For example, refunding one of two units paid at ₱80 each records an ₱80 refund and reduces revenue on the refund date. The final confirmation requires an explicit Yes/No choice about reversing the original cost of goods.

• Add Refund items to transaction details, in the order Close → Refund items → Print receipt. Select purchased items and quantities; previously refunded units cannot be refunded again.
• Show partial/full refund status, total refunded, remaining paid amount, and every refund's date/time, items, quantities, amount, and cost decision. History rows show the latest refund date when multiple refunds exist.
• Deduct refunds on their own dates across revenue, profit, trends, payment methods, product sales, customer spending, comparisons, and Excel exports. Order and sold-unit counts continue to describe original sales.
• Add a revenue-card tooltip showing gross sales, discounts, refunds, and net revenue. Add refund columns to transaction exports and a dated Refunds worksheet to analytics exports.
• Preserve original receipt amounts and leave inventory unchanged. Only accounts with the existing POS sell permission can confirm refunds; analytics-only users can view them.
• Persist append-only refunds with saved prices/costs, audit logging, an atomic version check, and retry-safe request IDs. Repeated requests and concurrent submissions cannot refund the same units twice.
• Color-code refund status in transaction history and refund details: "Partially refunded" in yellow, "Fully refunded" in red.
• Paginate the Product Sales and Sales by Customer tables in analytics, replacing the scroll-and-expand view. Each table defaults to 5 rows per page, has its own adjustable rows-per-page setting, and returns to page 1 when the date range, sort, or page size changes. Rank badges still reflect overall standing across all pages, and Excel exports still include every row.