Delta team/fix comment ui v2 (#11)

## 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.

Reviewed-on: #11
Co-authored-by: Duy Le Huu <duylh19@fpt.com>

presentation/shell/rail_project.py

@@ -42,6 +42,12 @@ class RailProjectMixin:
                 # No project yet: say so, and say what to do about it, instead of
                 # leaving an empty box and a button that silently does nothing.
                 self.nav_project.addItem(tr("app.nav.no_project"), "")
+            elif not current:
+                # Có project nhưng CHƯA chọn cái nào (mở app lên, hoặc vừa xoá
+                # project đang mở). Không có mục này thì combo rơi về mục 0 và
+                # chỉ bừa vào project đầu danh sách, trong khi cổng
+                # Cowork/GraphRAG vẫn đóng — hai chỗ nói hai đằng.
+                self.nav_project.insertItem(0, tr("app.nav.pick_project"), "")
             idx = self.nav_project.findData(current)
             if idx >= 0:
                 self.nav_project.setCurrentIndex(idx)