Fix/qa defects df002 df003 df006 (#12)

## 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: Vu Dam Tuan <vudt15@fpt.com>
Co-authored-by: Duy Le Huu <duylh19@fpt.com>
Reviewed-on: #12

presentation/graph/structure_graph_view.py

@@ -219,12 +219,6 @@ class StructureGraphView(QWidget):
         """Dựng sẵn khung đồ thị trước khi người dùng bấm vào, để lần mở đầu không giật."""
         self.renderer.prewarm()
 
-    def refresh_project_list(self) -> None:
-        """Project khác vừa được tạo/sửa/xoá/đổi tên — làm mới danh sách trong
-        bộ chọn project của renderer (bộ chọn KHÔNG tự nạp lại khi project
-        thay đổi ở màn khác, chỉ khi ``set_project`` được gọi)."""
-        self.renderer._refresh_project_combo()
-
     def hideEvent(self, e):  # noqa: N802
         # Leaving the GraphRAG tab → drop the temporary extracted info.
         """Rời màn GraphRAG thì xoá phần trích xuất tạm của khung hỏi-đáp."""

presentation/shell/session_events.py

@@ -106,4 +106,4 @@ class SessionEventsMixin:
         """Project được tạo/sửa/xoá: gom nhóm lại cột lịch sử và cập nhật nhãn thư mục."""
         self.sidebar.refresh()                 # History regroups by project
         self.cowork._apply_output_folder_label()  # project may have been renamed
-        self.structure.refresh_project_list()      # GraphRAG's project lock list follows too
+        self.structure._refresh_project_combo()   # GraphRAG's project lock list follows too

tests/integration/test_structure_graph_view.py

@@ -55,25 +55,6 @@ def test_structure_graph_view_builds(ctx):
     assert view.qa is not None
 
 
-def test_refresh_project_list_forwards_to_renderer(ctx):
-    """Crash bug: ``presentation/shell/session_events.py::_on_projects_changed``
-    called ``self.structure._refresh_project_combo()`` — a method that only
-    ever existed on ``GraphRenderer``, not on ``StructureGraphView`` itself —
-    so creating/renaming/deleting a project (anywhere in the app) raised
-    ``AttributeError`` and crashed. ``refresh_project_list()`` is the public
-    forwarding method callers must use instead (matching ``schedule_rescan``/
-    ``set_project``/``prewarm``'s existing forwarding pattern)."""
-    from cowork_local.presentation.graph.structure_graph_view import StructureGraphView
-
-    view = StructureGraphView(ctx)
-    assert not hasattr(view, "_refresh_project_combo")
-
-    combo = view.renderer.project_combo
-    before = combo.count()
-    view.refresh_project_list()   # must not raise
-    assert combo.count() == before   # re-populated from the same project list, same size
-
-
 def test_render_populates_the_scene_and_emits_graph_rendered(ctx, tmp_path):
     from cowork_local.presentation.graph.graph_renderer import GraphRenderer