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

tests/test_ms365_cloud_dialogs.py

@@ -0,0 +1,77 @@
+"""DF-007 — construction smoke tests for the two new MS365 cloud dialogs.
+Not a full characterization suite (see tests/test_monitoring_tab_container.py
+for the convention this follows) — just proves each dialog builds against a
+real AppConfig/AppContext without touching the network (Graph calls faked via
+monkeypatch)."""
+from __future__ import annotations
+
+import copy
+import os
+
+os.environ.setdefault("QT_QPA_PLATFORM", "offscreen")
+
+import pytest
+
+QApplication = pytest.importorskip("PySide6.QtWidgets").QApplication
+QDialog = pytest.importorskip("PySide6.QtWidgets").QDialog
+
+from cowork_local.config import AppConfig, DEFAULT_CONFIG
+from cowork_local.core import ms365_auth
+from cowork_local.core import ms365_graph as graph
+from cowork_local.ui.cloud_folder_picker_dialog import CloudFolderPickerDialog
+from cowork_local.ui.ms365_signin_dialog import Ms365SignInDialog, ensure_signed_in
+
+
+@pytest.fixture(scope="module")
+def qapp():
+    app = QApplication.instance() or QApplication([])
+    yield app
+
+
+@pytest.fixture()
+def config(tmp_path):
+    return AppConfig(data=copy.deepcopy(DEFAULT_CONFIG), path=tmp_path / "config.json")
+
+
+def test_signin_dialog_constructs(qapp, config) -> None:
+    dialog = Ms365SignInDialog(config)
+    assert dialog.windowTitle()
+
+
+def test_ensure_signed_in_short_circuits_when_already_signed_in(qapp, config, monkeypatch) -> None:
+    monkeypatch.setattr(ms365_auth, "is_signed_in", lambda cfg: True)
+    assert ensure_signed_in(None, config) is True
+
+
+def test_cloud_folder_picker_constructs_and_lists_onedrive_root(qapp, config, monkeypatch) -> None:
+    monkeypatch.setattr(ms365_auth, "get_access_token", lambda tenant_id, client_id: "fake-token")
+    monkeypatch.setattr(graph, "list_onedrive_files", lambda token, path="": [
+        {"name": "Documents", "folder": {}},
+        {"name": "readme.txt"},
+    ])
+
+    dialog = CloudFolderPickerDialog(config)
+
+    assert dialog._tree.topLevelItemCount() == 2
+    source = dialog.cloud_source()
+    assert source == {"provider": "onedrive", "site_id": "", "site_name": "", "remote_path": ""}
+
+
+def test_cloud_folder_picker_navigates_into_a_folder(qapp, config, monkeypatch) -> None:
+    monkeypatch.setattr(ms365_auth, "get_access_token", lambda tenant_id, client_id: "fake-token")
+
+    def fake_list(token, path=""):
+        if path == "":
+            return [{"name": "Documents", "folder": {}}]
+        if path == "Documents":
+            return [{"name": "report.docx"}]
+        return []
+
+    monkeypatch.setattr(graph, "list_onedrive_files", fake_list)
+
+    dialog = CloudFolderPickerDialog(config)
+    folder_item = dialog._tree.topLevelItem(0)
+    dialog._on_item_activated(folder_item, 0)
+
+    assert dialog._current_remote_path() == "Documents"
+    assert dialog.cloud_source()["remote_path"] == "Documents"