实现下单任务网关与本地 worker

按 docs/order-gateway.md 落地：第三个部署单元 app.gateway（:31109）承担任务队列
+ 状态镜像；本地 worker 在 app.trading.worker 内，按 RAKUTEN_ORDER_GATEWAY_URL
决定是否启动。规格 §5 最关键约束已守：租约过期绝不自动重投，恢复只能 reclaim，
worker 收到 lease_count>1 时先核对站点订单。

站点交互（加购/下单/付款/订单列表反查）按规格 §10 留接口缝，site_interact.py
全部 NotImplementedError，verify.py 恒返回 unknown——等真实账号实测后再填，
不写猜测的提交逻辑。

310 个测试全绿，覆盖规格 §9 验收清单 12 条；架构测试守住三方互不 import。

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/trading/main.py

@@ -10,10 +10,12 @@
 
 因此本服务只能单实例运行（或按账号分片），扩容靠抓取服务那一侧。
 
-当前只提供登录态的查询与重载；加购、下单、付款与订单监控在此基础上叠加。
+worker 启动条件：RAKUTEN_ORDER_GATEWAY_URL 非空。留空时本服务只跑登录态接口，
+不构造任何 worker 子组件（本地 DB / 证据目录 / 出站客户端都不创建）。
 """
 from __future__ import annotations
 
+import asyncio
 import logging
 from contextlib import asynccontextmanager
 
@@ -32,14 +34,41 @@ logger = logging.getLogger(__name__)
 
 
 def build_container() -> TradingContainer:
-    """构建交易服务容器，组装所有依赖"""
+    """构建交易服务容器：登录态会话始终构造，worker 仅在配置了网关 URL 时构造"""
     settings = get_settings()
-    return TradingContainer(settings=settings, auth_session=AuthSession(settings))
+    container = TradingContainer(settings=settings, auth_session=AuthSession(settings))
+
+    if settings.order_gateway_url:
+        # 延迟 import：未配置网关 URL 时不加载 worker 模块（也就不会拉起 aiosqlite 等）
+        from app.trading.worker.client import GatewayClient
+        from app.trading.worker.evidence import EvidenceStore
+        from app.trading.worker.local_db import LocalDB
+        from app.trading.worker.runner import WorkerRunner
+
+        client = GatewayClient(
+            settings.order_gateway_url,
+            settings.bearer_token,
+            timeout=max(60.0, settings.lease_max_wait_seconds + 10),
+        )
+        local_db = LocalDB(settings.trading_db_path_resolved)
+        evidence = EvidenceStore(settings.evidence_path)
+        runner = WorkerRunner(
+            settings=settings,
+            gateway_client=client,
+            local_db=local_db,
+            evidence=evidence,
+        )
+        container.worker_client = client
+        container.worker_local_db = local_db
+        container.worker_evidence = evidence
+        container.worker_runner = runner
+
+    return container
 
 
 @asynccontextmanager
 async def lifespan(app: FastAPI):
-    """应用生命周期管理：启动时加载登录态，关闭时释放 HTTP 客户端"""
+    """应用生命周期管理：登录态会话 + 可选 worker"""
     container = build_container()
     app.state.container = container
 
@@ -52,10 +81,42 @@ async def lifespan(app: FastAPI):
         container.settings.trading_port,
     )
     logger.info("当前环境：%s", container.settings.app_env)
+
     await container.auth_session.start()
+
+    worker_task: asyncio.Task | None = None
+    if container.worker_runner is not None:
+        # 顺序：先开本地 DB（worker 写证据前要先能写库），再起后台任务
+        assert container.worker_local_db is not None
+        assert container.worker_client is not None
+        await container.worker_local_db.start()
+        worker_task = asyncio.create_task(
+            container.worker_runner.run(), name="trading-worker"
+        )
+        logger.info(
+            "下单 worker 已启动：worker_id=%s gateway=%s",
+            container.settings.worker_id_effective,
+            container.settings.order_gateway_url,
+        )
+    else:
+        logger.info(
+            "未配置 RAKUTEN_ORDER_GATEWAY_URL，下单 worker 不启动（仅登录态接口）"
+        )
+
     try:
         yield
     finally:
+        if worker_task is not None:
+            container.worker_runner.stop()  # type: ignore[union-attr]
+            worker_task.cancel()
+            try:
+                await worker_task
+            except asyncio.CancelledError:
+                pass
+        if container.worker_local_db is not None:
+            await container.worker_local_db.close()
+        if container.worker_client is not None:
+            await container.worker_client.aclose()
         await container.auth_session.close()
         shutdown_telemetry()