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>

core/ms365_tools.py

@@ -168,6 +168,9 @@ _MAX_OUTPUT_CHARS = 20_000
 
 
 def _dump(data: Any) -> str:
+    """Kết quả tool dưới dạng JSON đã cắt ở ``_MAX_OUTPUT_CHARS`` — một hộp thư đầy
+    sẽ nuốt trọn cửa sổ ngữ cảnh nếu trả về nguyên vẹn.
+    """
     text = json.dumps(data, ensure_ascii=False, indent=2, default=str)
     if len(text) > _MAX_OUTPUT_CHARS:
         text = text[:_MAX_OUTPUT_CHARS] + f"\n…(truncated to {_MAX_OUTPUT_CHARS} chars)…"
@@ -197,6 +200,9 @@ def build_ms365_tools(config) -> Tuple[List[ToolSpec], Optional[Callable[[str, d
         return [], None
 
     def executor(name: str, args: dict) -> dict:
+        """Bộ thực thi các tool MS365 (mail, lịch, Teams, OneDrive, SharePoint), gói lỗi
+        thành kết quả thay vì ném ra.
+        """
         args = args or {}
         try:
             token = get_access_token(tenant_id, client_id)