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.

tests/test_monitoring_page_size.py

@@ -0,0 +1,70 @@
+"""DF-006 — the "Số dòng/trang" (rows per page) control: EventTable's
+page-size state (presentation/monitoring/shared/event_table.py) and its
+QComboBox wiring in build_filter_scaffold (.../shared/filter_scaffold.py).
+No dedicated test existed for this before — the design called for a
+user-visible/choosable item-per-page control, and this exercises it end to
+end (combo selection -> EventTable actually re-trimming its rows)."""
+from __future__ import annotations
+
+import os
+
+os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
+
+import pytest
+
+QApplication = pytest.importorskip("PySide6.QtWidgets").QApplication
+QWidget = pytest.importorskip("PySide6.QtWidgets").QWidget
+
+from cowork_local.presentation.monitoring.shared.event_table import (
+    PAGE_SIZE_OPTIONS, EventTable,
+)
+from cowork_local.presentation.monitoring.shared.filter_scaffold import build_filter_scaffold
+
+
+@pytest.fixture(scope="module")
+def qapp():
+    app = QApplication.instance() or QApplication([])
+    yield app
+
+
+def _events(n: int):
+    return [{"ts": f"2026-09-0{i % 9 + 1}T00:00:0{i % 9}", "kind": "tool_call",
+              "name": f"e{i}", "ok": True, "detail": ""} for i in range(n)]
+
+
+def test_default_page_size_matches_old_max_rows(qapp) -> None:
+    table = EventTable()
+    assert table.page_size() == 300
+    table.set_events(_events(500))
+    assert table.rowCount() == 300
+
+
+def test_set_page_size_retrims_without_reloading(qapp) -> None:
+    table = EventTable()
+    table.set_events(_events(500))
+    table.set_page_size(50)
+    assert table.page_size() == 50
+    assert table.rowCount() == 50
+
+
+def test_page_size_combo_is_only_added_when_requested(qapp) -> None:
+    page = QWidget()
+    table = EventTable()
+    parts = build_filter_scaffold(page, table, on_refresh=lambda: None, with_page_size=False)
+    assert "page_size_combo" not in parts
+
+
+def test_page_size_combo_changes_the_table(qapp) -> None:
+    page = QWidget()
+    table = EventTable()
+    table.set_events(_events(500))
+    parts = build_filter_scaffold(page, table, on_refresh=lambda: None, with_page_size=True)
+    combo = parts["page_size_combo"]
+    assert combo.count() == len(PAGE_SIZE_OPTIONS)
+    assert combo.currentData() == 300   # matches EventTable's current page_size
+
+    idx = PAGE_SIZE_OPTIONS.index(50)
+    combo.setCurrentIndex(idx)
+
+    assert table.page_size() == 50
+    assert table.rowCount() == 50