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_sync_execute_state_transition.py

@@ -0,0 +1,132 @@
+from __future__ import annotations
+
+from types import SimpleNamespace
+from unittest.mock import MagicMock
+
+import pytest
+
+from src.services.candidate.policy import FailoverAction
+from src.services.task.execute.exception_classification import (
+    CandidateErrorAction,
+    classify_candidate_error_action,
+)
+from src.services.task.execute.state_transition import (
+    SyncExecutionState,
+    resolve_execution_error_transition,
+)
+
+
+def _make_candidate() -> SimpleNamespace:
+    return SimpleNamespace(
+        provider=SimpleNamespace(id="p1", name="provider-1"),
+        endpoint=SimpleNamespace(id="e1"),
+        key=SimpleNamespace(id="k1"),
+    )
+
+
+@pytest.mark.parametrize(
+    ("raw_action", "expected"),
+    [
+        ("continue", CandidateErrorAction.RETRY_CURRENT),
+        ("break", CandidateErrorAction.NEXT_CANDIDATE),
+        ("raise", CandidateErrorAction.RAISE_ERROR),
+        ("unexpected", CandidateErrorAction.NEXT_CANDIDATE),
+        (None, CandidateErrorAction.NEXT_CANDIDATE),
+    ],
+)
+def test_classify_candidate_error_action(
+    raw_action: str | None, expected: CandidateErrorAction
+) -> None:
+    assert classify_candidate_error_action(raw_action) == expected
+
+
+def test_resolve_execution_error_transition_retry_and_consume_rectify_flag() -> None:
+    request_body_ref = {"_rectified_this_turn": True}
+    state = SyncExecutionState(
+        candidate_record_map={},
+        request_body_ref=request_body_ref,
+    )
+
+    transition = resolve_execution_error_transition(
+        action=CandidateErrorAction.RETRY_CURRENT,
+        state=state,
+        max_retries_for_candidate=2,
+        retry_index=1,
+    )
+
+    assert transition.failover_action == FailoverAction.RETRY
+    assert transition.max_retries == 3
+    assert request_body_ref["_rectified_this_turn"] is False
+
+
+def test_resolve_execution_error_transition_next_candidate() -> None:
+    state = SyncExecutionState(
+        candidate_record_map={},
+        request_body_ref={"_rectified_this_turn": True},
+    )
+
+    transition = resolve_execution_error_transition(
+        action=CandidateErrorAction.NEXT_CANDIDATE,
+        state=state,
+        max_retries_for_candidate=2,
+        retry_index=0,
+    )
+
+    assert transition.failover_action == FailoverAction.CONTINUE
+    assert transition.max_retries is None
+    assert state.request_body_ref == {"_rectified_this_turn": True}
+
+
+def test_sync_execution_state_resolve_candidate_record_id_fallback() -> None:
+    state = SyncExecutionState(
+        candidate_record_map={(2, 0): "r20"},
+        request_body_ref=None,
+    )
+
+    assert state.resolve_candidate_record_id(candidate_index=2, record_id=None) == "r20"
+    assert state.resolve_candidate_record_id(candidate_index=2, record_id="r22") == "r22"
+
+
+def test_sync_execution_state_raise_classified_error_uses_last_error() -> None:
+    err = ValueError("boom")
+    candidate = _make_candidate()
+    state = SyncExecutionState(
+        candidate_record_map={},
+        request_body_ref=None,
+        last_error=err,
+        last_candidate=candidate,
+    )
+    failure_ops = MagicMock()
+
+    with pytest.raises(ValueError, match="boom"):
+        state.raise_classified_error(
+            fallback_error=RuntimeError("fallback"),
+            failure_ops=failure_ops,
+            model_name="gpt-4.1",
+            api_format="openai_chat",
+        )
+
+    failure_ops.attach_metadata_to_error.assert_called_once_with(
+        err,
+        candidate,
+        "gpt-4.1",
+        "openai_chat",
+    )
+
+
+def test_sync_execution_state_raise_classified_error_fallback_error() -> None:
+    state = SyncExecutionState(
+        candidate_record_map={},
+        request_body_ref=None,
+    )
+    failure_ops = MagicMock()
+
+    with pytest.raises(RuntimeError, match="fallback"):
+        state.raise_classified_error(
+            fallback_error=RuntimeError("fallback"),
+            failure_ops=failure_ops,
+            model_name="gpt-4.1",
+            api_format="openai_chat",
+        )
+
+    failure_ops.attach_metadata_to_error.assert_not_called()