fix(ui): auto-grow item detail-description box + offer money columns to 8rem (consistency across invoice/order/offer)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/admin/pages/InvoiceDetail.tsx

@@ -302,6 +302,9 @@ function SortableInvoiceRow({
           value={item.item_description}
           onChange={(e) => onUpdate(index, "item_description", e.target.value)}
           placeholder="Volitelný"
+          multiline
+          minRows={1}
+          maxRows={8}
         />
         <Box
           sx={{
@@ -404,6 +407,9 @@ function SortableInvoiceRow({
               onUpdate(index, "item_description", e.target.value)
             }
             placeholder="Podrobný popis (volitelný)"
+            multiline
+            minRows={1}
+            maxRows={8}
             sx={{ "& input": { fontSize: "0.8rem", opacity: 0.8 } }}
           />
         </Box>