fix(qa): resolve DF-002 through DF-011 from QA defect tracking sheet

Batch of fixes for defects tracked in "Task Tracking Template.xlsx" (sheet
Defect Management), verified against the sheet's Root Cause/Cach xu ly
columns before this commit:

- DF-002: Co4E node status not reflected after tab switch + missing
  edit-lock on running/done nodes (node_property_panel.py, co4e_runs.py,
  co4e_workflow_crud.py, co4e_canvas_widget.py, co4e_flow_tabs.py,
  canvas_items.py)
- DF-003: hide the run.bat console window unless the app exits with an
  error (run.bat, scripts/console_visibility.ps1 - new)
- DF-004: floating Help Assistant icon covering the Send button after a
  window resize (presentation/shell/main_window.py)
- DF-005: "block network" toggle didn't stop ICMP/raw-socket tools like
  ping (infrastructure/filesystem/command_tools.py,
  security/command_risk_classifier.py)
- DF-006: Monitoring "gay nang khi log lon" - root cause was re-reading
  the ENTIRE audit log history every 3s tick, not missing pagination;
  bounded to a 30-day window (presentation/monitoring/monitoring_tab.py)
  AND added the "So dong/trang" page-size control the ticket also asked
  for (presentation/monitoring/shared/event_table.py,
  shared/filter_scaffold.py, tabs/action_logs_tab.py, tabs/mcp_tab.py,
  tabs/security_events_tab.py, i18n/agents_admin_tab.py)
- DF-007: support choosing a OneDrive/SharePoint folder as a project's
  working directory via Microsoft Graph, downloaded as a local mirror
  with manual sync (core/projects.py, core/ms365_graph.py,
  core/cloud_workspace_sync.py - new, ui/ms365_signin_dialog.py - new,
  ui/cloud_folder_picker_dialog.py - new, i18n/cloud_workspace.py - new,
  ui/workspace_tab.py)
- DF-008: AI-edit instruction box was a fixed-height single-line QLineEdit;
  replaced with an auto-expanding, Enter-to-send/Shift+Enter-newline input
  (presentation/folder/ai_file_editor_dialog.py)
- DF-011: run_command failed with WinError 267 for a project whose
  per-turn output directory had never been created
  (application/conversations/core_runtime_adapter.py)

DF-009 (AI-edit Apply/Discard buttons easy to miss) and DF-010 (AI reply
language - dev-confirmed not a bug) are intentionally NOT part of this
commit: DF-009 has no code fix yet (still "Assigned" in the sheet, only a
UX recommendation was recorded), DF-010 was rejected as expected behavior.

Tests: tests/test_cloud_workspace_sync.py, tests/test_ms365_cloud_dialogs.py,
tests/test_ai_file_editor_input.py, tests/test_monitoring_page_size.py (all
new, all passing). Full suite: 896 passed, 13 known-and-documented failures
unrelated to this change (an existing core/audit_log.py bug, this checkout
not being a git repo before now, and a repo/subprocess folder-naming
mismatch affecting ~66 characterization tests) - see the sheet's DF-006
Evidence column for details.

presentation/monitoring/shared/event_table.py

@@ -18,6 +18,7 @@ from .badges import action_label
 from .formatters import agent_avatar_icon, fmt_event_time
 
 _MAX_ROWS = 300
+PAGE_SIZE_OPTIONS = (50, 100, 300, 500, 1000)
 
 
 class _TimeItem(QTableWidgetItem):
@@ -70,6 +71,8 @@ class EventTable(QTableWidget):
         là thất bại nên cột ấy chỉ tốn chỗ.
         """
         self._show_result = show_result
+        self._page_size = _MAX_ROWS
+        self._last_events: List[dict] = []
         super().__init__(0, 7 if show_result else 6)
         self.setEditTriggers(QTableWidget.NoEditTriggers)
         self.setSelectionBehavior(QTableWidget.SelectRows)
@@ -98,13 +101,25 @@ class EventTable(QTableWidget):
         cols += [tr("monitoring.col_detail_block") if not self._show_result else tr("monitoring.col_detail")]
         self.setHorizontalHeaderLabels(cols)
 
+    def page_size(self) -> int:
+        """Số dòng đang hiển thị mỗi trang."""
+        return self._page_size
+
+    def set_page_size(self, n: int) -> None:
+        """Đổi số dòng hiển thị mỗi trang rồi vẽ lại với dữ liệu đã có sẵn
+        (không cần refresh lại từ nguồn — set_events() đã lưu lại lần đổ gần nhất)."""
+        self._page_size = n
+        self.set_events(self._last_events)
+
     def set_events(self, events: List[dict]) -> None:
-        """Đổ danh sách sự kiện vào bảng: mới nhất lên đầu, cắt ở ``_MAX_ROWS``.
+        """Đổ danh sách sự kiện vào bảng: mới nhất lên đầu, cắt ở ``self._page_size``
+        (đổi được qua ``set_page_size`` — control "Số dòng/trang" ở filter_scaffold.py).
 
         Tắt sắp xếp trong lúc đổ dữ liệu — để bật, Qt sắp lại sau mỗi dòng và việc
         nạp chậm đi theo bậc hai.
         """
-        events = sorted(events, key=lambda e: e.get("ts", ""), reverse=True)[:_MAX_ROWS]
+        self._last_events = events
+        events = sorted(events, key=lambda e: e.get("ts", ""), reverse=True)[:self._page_size]
         self.setSortingEnabled(False)
         self.setRowCount(len(events))
         for row, ev in enumerate(events):

presentation/monitoring/shared/filter_scaffold.py

@@ -16,13 +16,13 @@ from typing import Callable, Dict, Optional
 from PySide6.QtCore import Qt
 from PySide6.QtGui import QKeySequence, QShortcut
 from PySide6.QtWidgets import (
-    QApplication, QHBoxLayout, QLabel, QLineEdit, QPushButton, QSplitter,
-    QTableWidget, QVBoxLayout, QWidget,
+    QApplication, QComboBox, QHBoxLayout, QLabel, QLineEdit, QPushButton,
+    QSplitter, QTableWidget, QVBoxLayout, QWidget,
 )
 
 from ....i18n import tr
 from ....ui.icons import icon
-from .event_table import ClickOutsideCloser, EventTable
+from .event_table import PAGE_SIZE_OPTIONS, ClickOutsideCloser, EventTable
 from .event_detail_panel import EventDetailPanel
 
 
@@ -47,11 +47,12 @@ def _sync_event_detail(table: EventTable, panel: EventDetailPanel) -> None:
 def build_filter_scaffold(
     page: QWidget, table: QTableWidget, *, on_refresh: Callable[[], None],
     title_key: Optional[str] = None, with_search: bool = True,
-    with_detail: bool = False,
+    with_detail: bool = False, with_page_size: bool = False,
     on_ai_filter: Optional[Callable[[QLineEdit, QPushButton], None]] = None,
 ) -> Dict[str, object]:
     """Dựng khung chung cho một tab sự kiện: tiêu đề, nút làm mới, ô tìm kiếm,
-    nút lọc bằng AI và panel chi tiết.
+    nút lọc bằng AI, control "Số dòng/trang" (nếu ``with_page_size``) và panel
+    chi tiết.
 
     Bốn tab sự kiện của màn Giám sát chỉ khác nhau ở nguồn dữ liệu, nên phần vỏ
     này được dựng một lần và dùng chung.
@@ -88,6 +89,23 @@ def build_filter_scaffold(
             ai_btn.clicked.connect(lambda: on_ai_filter(search, ai_btn))
         row.addWidget(search, 1)
         row.addWidget(ai_btn)
+        if with_page_size and isinstance(table, EventTable):
+            # DF-006: the item-per-page count was never surfaced anywhere in
+            # the UI (design called for it) — EventTable already trims to a
+            # page size internally (default 300), this just makes that
+            # number visible AND user-choosable instead of a fixed constant.
+            page_size_lbl = QLabel(tr("monitoring.page_size_label"))
+            page_size_combo = QComboBox()
+            for n in PAGE_SIZE_OPTIONS:
+                page_size_combo.addItem(str(n), n)
+            current = table.page_size()
+            page_size_combo.setCurrentIndex(
+                PAGE_SIZE_OPTIONS.index(current) if current in PAGE_SIZE_OPTIONS else 2)
+            page_size_combo.currentIndexChanged.connect(
+                lambda i: table.set_page_size(page_size_combo.itemData(i)))
+            row.addWidget(page_size_lbl)
+            row.addWidget(page_size_combo)
+            parts.update(page_size_label=page_size_lbl, page_size_combo=page_size_combo)
         lay.addLayout(row)
         parts.update(filter_edit=search, ai_filter_btn=ai_btn)