feat(cashier): add server-side pagination to GL entries closing report

- Backend: add offset/limit query params to gl-entries endpoint
- Backend: return totalFilteredRecords + pageItems response structure
- Backend: totals (DR/CR) computed from all records regardless of page
- Frontend: integrate mat-paginator with page size options 10/20/50/100
- Frontend: reset offset to 0 on filter change

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/cashier/closing-cash-report/closing-cash-report.component.html

@@ -262,12 +262,20 @@
           </tbody>
           <tfoot>
             <tr class="gl-foot">
-              <td colspan="6" class="gl-foot__label">Total</td>
+              <td colspan="6" class="gl-foot__label">Total (All Pages)</td>
               <td class="num gl-amt--dr gl-foot__val">₹{{ glTotalDr | number: '1.2-2' }}</td>
               <td class="num gl-amt--cr gl-foot__val">₹{{ glTotalCr | number: '1.2-2' }}</td>
             </tr>
           </tfoot>
         </table>
+        <mat-paginator
+          [length]="glTotal"
+          [pageSize]="glPageSize"
+          [pageSizeOptions]="glPageSizeOptions"
+          [pageIndex]="glOffset / glPageSize"
+          showFirstLastButtons
+          (page)="onGlPageChange($event)"
+        ></mat-paginator>
       }
     </div>
   }