merge: hoàn tất merge origin/feature/teamhoa/r05-r06 vào feature/delta-team/epic-R04

Resolve 3 file conflict:
- docs/refactor/Refactoring_Checklist.md: giữ nội dung incoming (phía HEAD
  trống ở đoạn conflict).
- tests/integration/test_routing_surfaces.py: khôi phục từ incoming (bị mất
  ở merge trước đó), điều chỉnh lại cho khớp API hiện tại của
  RoutingApplicationService (resolve()/RouteEvaluation/mode_resolver thay vì
  route_turn()/mode_reader cũ), bỏ 2 test pin một lớp RoutingDecision không
  còn tồn tại trên nhánh này.
- ui/folder_tab.py: chấp nhận xoá (deleted by them) — đã được thay thế hoàn
  toàn bởi presentation/folder/* (R08-T12), không còn nơi nào import module
  cũ.

Sửa thêm 2 chỗ lệch API bị auto-merge không báo conflict (phát hiện khi chạy
lại test):
- presentation/folder/ai_edit_model_resolver.py + ai_file_editor_dialog.py:
  AiEditModelResolver.apply_routing() gọi route_turn() đã bị xoá khỏi
  RoutingApplicationService — chuyển sang build_routing_application_service()
  .resolve(RoutingRequest(...)) giống chat_panel.py/co4e_chat.py; sửa luôn
  chữ ký _confirm_routing_switch nhận thêm timeout cho khớp contract confirm
  mới.
- config.py: import JsonConfigRepository ở đầu file gây circular import với
  core/tasks.py (cần CONFIG_DIR) qua chuỗi mới
  infrastructure/persistence/json/task_repository_impl.py (R07). Dời import
  xuống ngay trước chỗ dùng đầu tiên.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

infrastructure/persistence/json/__init__.py

@@ -1,8 +1,10 @@
-"""JSON-file persistence adapters: crash-safe writes, AtomicJsonFile and repositories."""
+"""JSON-file persistence adapters: crash-safe writes and the workspace/
+conversation/task repositories built on them (EPIC R06, R07)."""
 
 from .atomic_json_file import AtomicJsonFile
 from .atomic_write import write_json
 from .conversation_repository_impl import ConversationRepository
+from .task_repository_impl import TaskRepository
 from .workspace_repository_impl import WorkspaceRepository
 
 __all__ = [
@@ -10,4 +12,5 @@ __all__ = [
     "write_json",
     "WorkspaceRepository",
     "ConversationRepository",
+    "TaskRepository",
 ]

infrastructure/persistence/json/task_repository_impl.py

@@ -0,0 +1,63 @@
+"""TaskRepository - an object-shaped, atomic-write-backed facade over
+``core/tasks.py`` (R07-T01).
+
+``core/tasks.py``'s module-level functions (``list_tasks``, ``load_task``,
+``save_task``, ``delete_task``, ``new_task``, ``duplicate_task``) are still
+what every existing call site (``core/task_scheduler.py``,
+``core/task_executors.py``, ``ui/schedule_task_tab.py``) uses, and stay that
+way - ``save_task`` now writes through :func:`atomic_write.write_json`
+itself (R07-T01, same class of durability fix already applied to
+``core/projects.py``/``core/history.py`` at R06-T02), so the fix applies
+whether or not a caller ever touches this class.
+
+This repository exists for the application layer
+(``application/scheduling``, R07-T04) to depend on an interface instead of
+reaching into ``core/`` directly. It is a thin pass-through today, not a
+re-implementation: same on-disk format, same directory, same functions
+underneath.
+"""
+from __future__ import annotations
+
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+
+from cowork_local.core.tasks import (
+    TASKS_DIR,
+    delete_task,
+    duplicate_task,
+    list_tasks,
+    load_task,
+    new_task,
+    save_task,
+)
+
+
+class TaskRepository:
+    """CRUD over task dicts (see ``core/tasks.py::DEFAULT_TASK`` for shape),
+    scoped to one ``directory`` (defaults to the app's real ``TASKS_DIR``;
+    tests pass a ``tmp_path`` so nothing touches the user's real config
+    folder)."""
+
+    def __init__(self, directory: Optional[Path] = None) -> None:
+        self._directory = directory or TASKS_DIR
+
+    def list(self) -> List[Dict[str, Any]]:
+        return list_tasks(self._directory)
+
+    def get(self, task_id: str) -> Optional[Dict[str, Any]]:
+        return load_task(task_id, self._directory)
+
+    def save(self, task: Dict[str, Any]) -> Path:
+        return save_task(task, self._directory)
+
+    def create(self, title: str = "", **overrides: Any) -> Dict[str, Any]:
+        return new_task(title, **overrides)
+
+    def duplicate(self, task: Dict[str, Any]) -> Dict[str, Any]:
+        return duplicate_task(task)
+
+    def delete(self, task_id: str) -> None:
+        delete_task(task_id, self._directory)
+
+
+__all__ = ["TaskRepository"]