fix(ui): widen 'Jedn. cena' column in invoice + issued-order line-item tables (5.5rem -> 8rem)

The editable unit-price number input was cramped (5.5rem, same as qty/unit); widened to 8rem to match the Celkem column and the read-only detail view, so real prices fit.

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

src/admin/pages/InvoiceDetail.tsx

@@ -735,7 +735,7 @@ export default function InvoiceDetail() {
     bankAccountsQuery.isLoading,
     bankAccountsQuery.data,
     customersQuery.isLoading,
-  ]);  
+  ]);
 
   // Create mode: populate form from query data
   useEffect(() => {
@@ -813,7 +813,7 @@ export default function InvoiceDetail() {
     orderDataQuery.data,
     companySettings,
     bankAccounts,
-  ]);  
+  ]);
 
   // Capture initial snapshot for dirty-checking once data sync completes.
   // Edit mode: captured inside the sync effect from raw query data.
@@ -2113,7 +2113,7 @@ export default function InvoiceDetail() {
                         <TableCell sx={{ width: "5.5rem" }} align="center">
                           Jednotka
                         </TableCell>
-                        <TableCell sx={{ width: "5.5rem" }} align="center">
+                        <TableCell sx={{ width: "8rem" }} align="center">
                           Jedn. cena
                         </TableCell>
                         {form.apply_vat ? (

src/admin/pages/IssuedOrderDetail.tsx

@@ -1120,7 +1120,7 @@ export default function IssuedOrderDetail() {
                         <TableCell sx={{ width: "5.5rem" }} align="center">
                           Jednotka
                         </TableCell>
-                        <TableCell sx={{ width: "5.5rem" }} align="center">
+                        <TableCell sx={{ width: "8rem" }} align="center">
                           Jedn. cena
                         </TableCell>
                         {form.apply_vat ? (