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>

tests/fakes/fake_tool_policy.py

@@ -0,0 +1,44 @@
+"""ToolPolicyGateway giả — để N3 (Co4E) chạy được khi Team Hoa chưa cài đặt.
+
+Mặc định cho qua hết, vì phần lớn test Co4E quan tâm tới luồng workflow chứ
+không phải chính sách. Test nào cần kiểm nhánh bị chặn thì lập trình câu trả
+lời::
+
+    gate = FakeToolPolicyGateway(rules={"run_command": deny("cấm trong Co4E")})
+"""
+from __future__ import annotations
+
+from typing import Callable, Dict
+
+from cowork_local.domain.security.tool_policy import (
+    PolicyDecision, ToolCallRequest, allow,
+)
+
+
+class FakeToolPolicyGateway:
+    """Cổng chính sách trong bộ nhớ, có ghi lại đã hỏi những gì."""
+
+    def __init__(self, rules: Dict[str, PolicyDecision] | None = None,
+                 default: PolicyDecision | None = None,
+                 decide: Callable[[ToolCallRequest], PolicyDecision] | None = None):
+        #: {tên tool: quyết định} — tra trước default
+        self.rules = dict(rules or {})
+        self.default = default or allow()
+        #: hàm tự quyết, dùng khi cần logic phức tạp hơn tra bảng
+        self._decide = decide
+        #: mọi lời gọi đã đi qua — để test khẳng định "có hỏi cổng không"
+        self.seen: list[ToolCallRequest] = []
+
+    def check(self, request: ToolCallRequest) -> PolicyDecision:
+        self.seen.append(request)
+        if self._decide is not None:
+            return self._decide(request)
+        return self.rules.get(request.name, self.default)
+
+    # ---- tiện cho test --------------------------------------------------
+    def asked_for(self, name: str) -> bool:
+        return any(r.name == name for r in self.seen)
+
+    @property
+    def call_count(self) -> int:
+        return len(self.seen)