PDF UX: hide main Execute button for pages tab, reset download on tab switch

- Pages tab (delete/rotate/reorder) has inline action buttons, no main Execute
- Download link hidden when switching tabs
- Result section reset on tab switch

public/pdf.html

@@ -1383,9 +1383,13 @@
             document.querySelectorAll('.op-panel').forEach(p => p.classList.remove('active'));
             const panel = document.getElementById('panel-' + tab.dataset.op);
             if (panel) panel.classList.add('active');
+            // Reset result and progress
             stepResult.style.display = 'none';
-            actionWrap.style.display = 'block';
+            downloadLink.style.display = 'none';
             progressWrap.style.display = 'none';
+            // Hide "Выполнить" for tabs with inline actions (pages have own buttons)
+            const noMainButton = ['pages'];
+            actionWrap.style.display = noMainButton.includes(tab.dataset.op) ? 'none' : 'block';
         });
     });