Fix/qa defects df002 df011 (#9)

## Summary

What changed and why?

## Change Type

- [ ] Cowork feature
- [ ] Bug fix
- [ ] Core AI contribution
- [ ] Test / hardening
- [ ] Performance
- [ ] Documentation

## Related Work

Cowork Task:

Core Repo: http://34.143.229.138/gitea-admin/fsg-ai-core-assets

Core AI Issue:

Core Task:

Related PR:

## Scope

What is intentionally included?

What is intentionally NOT included?

## Validation

- [ ] Unit tests
- [ ] Integration tests
- [ ] Manual verification
- [ ] Regression check

Commands / evidence:

## Security Impact

Permission / credential / network / customer data impact:

## Compatibility

- [ ] No breaking change
- [ ] Breaking change documented

## Reviewer Notes

Anything Cowork reviewers should pay attention to.

---------

Co-authored-by: thanhnv <thanhnv.ip@gmail.com>
Co-authored-by: Vu Dam Tuan <vudt15@fpt.com>
Reviewed-on: #9

presentation/monitoring/tabs/security_events_tab.py

@@ -31,13 +31,15 @@ class SecurityEventsTab(QWidget):
         parts = build_filter_scaffold(
             self, self.table, on_refresh=on_refresh_all,
             title_key="monitoring.security_events_title",
-            with_search=True, with_detail=True, on_ai_filter=self._start_ai_filter)
+            with_search=True, with_detail=True, with_page_size=True,
+            on_ai_filter=self._start_ai_filter)
         self.title_lbl = parts["title_lbl"]
         self.title_key = parts["title_key"]
         self.title_refresh_btn = parts["title_refresh_btn"]
         self.filter_edit = parts["filter_edit"]
         self.ai_filter_btn = parts["ai_filter_btn"]
         self.detail_panel = parts["detail_panel"]
+        self.page_size_label = parts["page_size_label"]
 
     def set_events(self, events: List[dict]) -> None:
         """Đổ danh sách sự kiện vào bảng."""
@@ -50,6 +52,7 @@ class SecurityEventsTab(QWidget):
         self.detail_panel.retranslate()
         self.title_lbl.setText(tr(self.title_key))
         self.title_refresh_btn.setText(tr("monitoring.refresh"))
+        self.page_size_label.setText(tr("monitoring.page_size_label"))
 
     def _start_ai_filter(self, search: QLineEdit, ai_btn: QPushButton) -> None:
         """Nhờ AI dịch câu tìm kiếm tự nhiên thành từ khoá lọc."""