Feature/delta team/epic r04 (#7)

## Summary

epic r04 - begin refactor

## Change Type

- [x] 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: Anh Tran Nguyen Minh <anhtnm1@fpt.com>
Co-authored-by: Huong Le Thi Thien <huongltt35@fpt.com>
Co-authored-by: Nam Pham Dinh Thanh <nampdt@fpt.com>
Co-authored-by: Vu Dam Tuan <vudt15@fpt.com>
Co-authored-by: Hiep Ha Van <hiephv3@fpt.com>
Co-authored-by: Lam Hoang Van <lamhv7@fpt.com>
Reviewed-on: #7
Co-authored-by: Duy Le Huu <duylh19@fpt.com>

presentation/shared/web_engine_support.py

@@ -0,0 +1,38 @@
+"""HAS_WEB_ENGINE — whether ``QWebEngineView`` is safe to construct here
+(R08-T12/T14, extracted from ``ui/structure_graph_view.py``, lines 25-48 of
+its original 1035-line version — the ONLY place this detection logic lived;
+``ui/folder_tab.py`` used to import it FROM that module via a try/except).
+"""
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+
+def _frozen_onefile() -> bool:
+    """True only for a PyInstaller ONEFILE build. Onefile extracts itself to a
+    temp dir (sys._MEIPASS under %TEMP%), where the QtWebEngine helper process
+    can't run — creating a QWebEngineView hard-crashes the app (reported as
+    "click the graph tab → app closes"). A ONEDIR build keeps _MEIPASS as the
+    ``_internal`` folder right next to the exe, where WebEngine works fine, so
+    it keeps the full embedded D3/HTML view."""
+    if not getattr(sys, "frozen", False):
+        return False
+    meipass = getattr(sys, "_MEIPASS", "")
+    if not meipass:
+        return False
+    try:
+        return Path(meipass).resolve().parent != Path(sys.executable).resolve().parent
+    except OSError:  # can't tell → play safe: use the native/fallback view
+        return True
+
+
+try:  # WebEngine + WebChannel are optional PySide6 add-ons
+    from PySide6.QtWebEngineWidgets import QWebEngineView  # noqa: F401
+    from PySide6.QtWebChannel import QWebChannel  # noqa: F401
+    HAS_WEB_ENGINE = not _frozen_onefile()
+except Exception:  # pragma: no cover
+    HAS_WEB_ENGINE = False
+
+
+__all__ = ["HAS_WEB_ENGINE"]