refactor(task): 拆分 TaskService 并重构任务生命周期

- 将 task 公共协议/上下文/异常/schema 下沉到 core，并迁移 polling 目录
- 新增 execute/submit/video 子模块，拆分同步执行、异步提交流程、错误处理与视频任务操作
- 收敛 TaskService 为门面编排，内部委派到 SyncTaskExecutionService、AsyncTaskSubmitService、VideoTaskOperationsService
- 重构 main 生命周期管理：引入 LifecycleState，拆分启动与关闭流程
- 删除未使用的 TaskExecuteFacadeService 与 TaskSubmitFacadeService

Closes #201

Co-authored-by: AAEE86 <ppk0227@hotmail.com>

tests/services/test_video_task_poller.py

@@ -1,10 +1,12 @@
-from types import SimpleNamespace
+from types import SimpleNamespace
+from typing import cast
 from unittest.mock import AsyncMock, MagicMock
 
 import pytest
 
 from src.core.api_format.conversion.internal_video import InternalVideoPollResult, VideoStatus
-from src.services.task.impl.video_poller import VideoTaskPollerAdapter
+from src.models.database import VideoTask
+from src.services.task.video.poller_adapter import VideoTaskPollerAdapter
 
 
 @pytest.mark.asyncio
@@ -13,11 +15,14 @@ async def test_poll_task_status_routes_gemini_video_to_gemini(
 ) -> None:
     adapter = VideoTaskPollerAdapter()
 
-    task = SimpleNamespace(
-        endpoint_id="e1",
-        key_id="k1",
-        provider_api_format="gemini:video",
-        external_task_id="operations/123",
+    task = cast(
+        VideoTask,
+        SimpleNamespace(
+            endpoint_id="e1",
+            key_id="k1",
+            provider_api_format="gemini:video",
+            external_task_id="operations/123",
+        ),
     )
     endpoint = SimpleNamespace(id="e1", base_url="https://example.com", api_format="gemini:video")
     key = SimpleNamespace(id="k1", api_key="enc")
@@ -25,12 +30,12 @@ async def test_poll_task_status_routes_gemini_video_to_gemini(
     monkeypatch.setattr(adapter, "_get_endpoint", lambda _db, _id: endpoint)
     monkeypatch.setattr(adapter, "_get_key", lambda _db, _id: key)
     monkeypatch.setattr(
-        "src.services.task.impl.video_poller.crypto_service.decrypt", lambda _v: "decrypted"
+        "src.services.task.video.poller_adapter.crypto_service.decrypt", lambda _v: "decrypted"
     )
 
     auth_info = SimpleNamespace(auth_header="authorization", auth_value="Bearer x")
     monkeypatch.setattr(
-        "src.services.task.impl.video_poller.get_provider_auth",
+        "src.services.task.video.poller_adapter.get_provider_auth",
         AsyncMock(return_value=auth_info),
     )