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/routing/switch_controller.py

@@ -141,6 +141,7 @@ class PendingSwitchRegistry:
     _RESOLVE_WAIT_SEC = 600.0
 
     def __init__(self, clock: Callable[[], float] = time.time) -> None:
+        """``clock`` tiêm được để test kiểm hết hạn mà không phải chờ thật."""
         self._items: Dict[str, PendingSwitch] = {}
         self._events: Dict[str, threading.Event] = {}
         self._running: Set[str] = set()
@@ -180,6 +181,7 @@ class PendingSwitchRegistry:
             return ps
 
     def _maybe_expire_locked(self, ps: PendingSwitch) -> None:
+        """Đánh dấu hết hạn nếu đã quá hạn chờ. Gọi trong lúc đang giữ khoá."""
         if ps.status == SwitchStatus.PENDING and self._clock() >= ps.expires_at:
             ps.status = SwitchStatus.EXPIRED
 
@@ -270,6 +272,7 @@ class PendingSwitchRegistry:
         return removed
 
     def pending_ids(self) -> List[str]:
+        """Id các đề nghị còn đang chờ (đã loại những cái vừa hết hạn)."""
         with self._lock:
             return [
                 rid for rid, ps in self._items.items()