feat(R04): run every Cowork turn through ConversationApplicationService

R04-T03 — the turn lifecycle, extracted from `core/chat_agent.py::run_cowork`
into `application/conversations/`. The 260-line body mixed the lifecycle (step
budget, cancel checks, guard -> preview -> gate -> execute ordering, sandbox
tidy-up) with the machinery doing each step, and reaching any of it meant
standing up a Qt widget and a worker thread. It is now a plain object driven
through two Protocols and six callables (`turn_runtime.py`), with the concrete
`core/*` wiring confined to `core_runtime_adapter.py` — the same shape R03 used
for routing. Faithful port, not an improvement pass: where the original had a
quirk (the step-ceiling note only merges into the answer when the last message
is the assistant's) the quirk is preserved and commented.

R04-T04 — `ui/cowork_tab.py::build_job` no longer calls run_cowork. It captures
the widget's state at submit time, builds the request via the new
`cowork_turn_request.py` and executes it. `execute(..., messages=...)` hands the
widget's own list over because `_reattach_running_turn` replays from it WHILE
the worker appends and `_finalize_turn` slices it afterwards — a private list
would break both silently.

R04-T05 — `core/task_executors.py`'s cowork branch shares the same engine. All
five unattended-run behaviours stay put (plan reminder, history_ready, History
autosave per assistant message, timeout notice, plan_incomplete_reason), and
`_unattended_prompt` now expresses the load-bearing prefix order in one
readable call instead of three successive rebindings.

Verification: 74 new tests (364 passed, 1 skipped overall; check_imports PASS).
The two that matter most:
- `test_conversation_service_parity.py` runs the same scripted turn through
  run_cowork AND the service and compares the event stream, the resulting
  conversation and the advertised tool list across 7 scenarios;
- `test_task_executor_turn.py` was written BEFORE the migration and passed 8/8
  against the old code, then unchanged against the new.

Known: `ui/cowork_tab.py` (416 -> 455) and `core/task_executors.py` (476 -> 524)
stay above the 400-LOC limit. Both were already over it before this change;
bringing them under needs the R08 / R07 decompositions.

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

docs/refactor/Refactoring_Checklist.md

@@ -135,16 +135,22 @@
 * **Team chịu trách nhiệm**: 🔵 **Team Duy** (Chủ trì)
 * **Mục tiêu**: Đóng gói input turn chat thành `ConversationExecutionRequest` bất biến, điều phối vòng đời qua `ConversationApplicationService` và phát sinh sự kiện `AgentEvent` có định kiểu.
 
-- [ ] **R04-T01 (Team Duy)**: Định nghĩa immutable dataclass `ConversationExecutionRequest` ➔ `domain/agents/conversation_execution_request.py`  
-  *Start: `____-__-__ __:__` | End: `____-__-__ __:__`*
-- [ ] **R04-T02 (Team Duy)**: Chuẩn hóa các sự kiện `AgentEvent` (TextChunk, ToolCallStarted, ToolCallResult, Error) ➔ `domain/agents/agent_event.py`  
-  *Start: `____-__-__ __:__` | End: `____-__-__ __:__`*
-- [ ] **R04-T03 (Team Duy)**: Xây dựng `ConversationApplicationService` điều phối thực thi từ `core/chat_agent.py` ➔ `application/conversations/conversation_application_service.py`  
-  *Start: `____-__-__ __:__` | End: `____-__-__ __:__`*
-- [ ] **R04-T04 (Team Duy)**: Di chuyển `ui/cowork_tab.py::build_job` sang sử dụng `ConversationExecutionRequest`  
-  *Start: `____-__-__ __:__` | End: `____-__-__ __:__`*
-- [ ] **R04-T05 (Team Duy)**: Di chuyển `core/task_executors.py` sang dùng chung `ConversationApplicationService`  
-  *Start: `____-__-__ __:__` | End: `____-__-__ __:__`*
+- [x] **R04-T01 (Team Duy)**: Định nghĩa immutable dataclass `ConversationExecutionRequest` ➔ `domain/agents/conversation_execution_request.py`  
+  *Start: `2026-08-23 00:56` | End: `2026-08-23 01:00`*
+- [x] **R04-T02 (Team Duy)**: Chuẩn hóa các sự kiện `AgentEvent` (TextChunk, ToolCallStarted, ToolCallResult, Error) ➔ `domain/agents/agent_event.py` (+ `domain/agents/agent_event_codec.py` — shim dịch legacy dict, tách riêng để giữ LOC < 400 và để xoá gọn sau R08)  
+  *Start: `2026-08-23 01:00` | End: `2026-08-23 01:08`*
+- [x] **R04-T03 (Team Duy)**: Xây dựng `ConversationApplicationService` điều phối thực thi từ `core/chat_agent.py` ➔ `application/conversations/conversation_application_service.py` (+ `turn_runtime.py` định nghĩa 2 port/6 callable, `core_runtime_adapter.py` cầu nối sang `core/*`, `domain/agents/agent_result.py`)  
+  *Start: `2026-08-23 01:08` | End: `2026-08-23 07:10`*  
+  Chưa đổi call site nào — `run_cowork` giữ nguyên (Co4E vẫn dùng); việc chuyển call site là T04/T05. Bằng chứng tương đương: `tests/integration/test_conversation_service_parity.py` chạy cùng 1 script provider qua 2 đường và so khớp từng event/message/tool list trên 7 kịch bản.
+- [x] **R04-T04 (Team Duy)**: Di chuyển `ui/cowork_tab.py::build_job` sang sử dụng `ConversationExecutionRequest`  
+  *Start: `2026-08-23 07:10` | End: `2026-08-23 07:23`*  
+  `build_job` không còn gọi `run_cowork`: nó chụp state widget tại submit time ➔ `build_cowork_turn_request()` (mới, `application/conversations/cowork_turn_request.py`) ➔ `ConversationApplicationService`. Thêm `combine_instructions()` vào `turn_runtime.py` (project context + admin agent, T05 dùng lại) và tham số `messages=` cho `execute()` để service append vào **đúng list của widget** — `_reattach_running_turn` đọc list đó trong lúc turn đang chạy và `_finalize_turn` slice nó sau đó. Kiểm chứng: `tests/integration/test_cowork_tab_turn.py` gọi thẳng `CoworkTab.build_job` (widget stub, không cần Qt) và chạy turn thật với `FakeProvider`.  
+  ⚠️ `ui/cowork_tab.py` 416 ➔ 455 LOC — file này **vốn đã vượt 400 trước khi sửa**; phân rã thuộc EPIC R08.
+- [x] **R04-T05 (Team Duy)**: Di chuyển `core/task_executors.py` sang dùng chung `ConversationApplicationService`  
+  *Start: `2026-08-23 07:23` | End: `2026-08-23 07:31`*  
+  Nhánh `task_type == "cowork"` của `_run_agent` gọi service thay vì `run_cowork`; 5 hành vi riêng của unattended run giữ nguyên (plan reminder, `history_ready`, autosave History mỗi `assistant_done`, timeout notice, `plan_incomplete_reason`). Tách `_unattended_prompt()` dùng `combine_instructions` để thứ tự reminder → skill → persona → prompt nằm ở 1 chỗ đọc được. Lưới an toàn: `tests/integration/test_task_executor_turn.py` viết **trước** khi migrate và pass 8/8 trên code cũ, vẫn pass sau khi migrate.  
+  ⚠️ `core/task_executors.py` 476 ➔ 524 LOC — file này **vốn đã vượt 400 trước khi sửa**; phân rã thuộc EPIC R07 (`application/scheduling/`).  
+  Còn lại gọi `run_cowork`: `core/co4e_runner.py` (×2) và `ui/co4e_tab.py` — phân hệ Co4E của 🟣 Team Nam, R04 không chạm theo luật 1 file 1 team.
 
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