拆分抓取与交易服务

把需要账号登录态的链路从抓取服务里拆出成独立进程。分界线不是「要不要登录」，
而是抓取无状态、幂等、可多开实例，而交易的写操作不可逆、登录态全局唯一、
订单监控是常驻轮询——同进程时抓取一扩容就会复制出 N 份登录态与 N 个轮询，
同一账号会被并发操作。

- app/shared：配置、错误码、日志、ApiResponse 信封 + Bearer 鉴权 + 异常处理器、
  导航请求头构造器
- app/scraping：站点常量、会话、解析器与 10 个抓取接口，:31107，可多开
- app/trading：登录态查询/重载与健康检查，:31108，只能单实例
- 依赖方向锁为 scraping→shared、trading→shared，两侧互不 import；
  tests/test_architecture.py 用 AST 检查 import 并校验两个 app 的路径不串
- 登录态 UA 在 trading 独立持有：与抓取 UA 值相同但变更理由不同，抓取 UA 为绕
  反爬可随时调整，登录 UA 一改可能触发设备校验使已落盘 cookie 失效
- scripts/login.py 与 AuthSession 共用 auth_site.PROFILES 与 is_logged_in，判据只写一遍
- 同一镜像两个启动命令，交易容器覆盖 command 并设 RAKUTEN_HEALTH_PORT

同时带上此前未提交的 ラクマ 分类接口与登录态基础设施。

验证：239 个离线用例全绿；两个入口真实启动，/health 与鉴权正常。
未验证：真实探测登录态（当前开发机无外网，对站点的连接全部超时）。

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/test_api.py

@@ -7,13 +7,15 @@ from __future__ import annotations
 import pytest
 from fastapi.testclient import TestClient
 
-from app.core.config import get_settings
-from app.core.errors import ItemNotFoundError, OffIchibaRedirectError, UpstreamBlockedError
-from app.main import create_app
-from app.models.scrape import (
+from app.shared.config import get_settings
+from app.shared.errors import ItemNotFoundError, OffIchibaRedirectError, UpstreamBlockedError
+from app.scraping.main import create_app
+from app.scraping.models.scrape import (
     GenreData,
     GenreNode,
     ItemDetailData,
+    RakumaCategoryData,
+    RakumaCategoryNode,
     RakumaItemDetailData,
     RakumaSearchItem,
     RakumaSearchResultData,
@@ -90,6 +92,7 @@ class StubRakumaClient:
 
     def __init__(self) -> None:
         self.search_payload = None
+        self.category_payload = None
         self.detail_payload = None
         self.shop_detail_payload = None
         self.shop_items_payload = None
@@ -107,6 +110,15 @@ class StubRakumaClient:
             items=[RakumaSearchItem(item_id="abc", item_name="商品", price=6299)],
         )
 
+    async def categories(self, payload) -> RakumaCategoryData:
+        self.category_payload = payload
+        return RakumaCategoryData(
+            category_id=payload.category_id or "",
+            name="エンタメ/ホビー" if payload.category_id else "",
+            total_count=1686,
+            children=[RakumaCategoryNode(category_id="786", name="ゲームソフト/ゲーム機本体")],
+        )
+
     async def item_detail(self, payload) -> RakumaItemDetailData:
         self.detail_payload = payload
         if self.raise_on_detail:
@@ -346,6 +358,7 @@ def test_shop_items_requires_an_identifier(client):
     "path",
     [
         "/api/rakuma/search",
+        "/api/rakuma/categories",
         "/api/rakuma/item_detail",
         "/api/rakuma/shop_detail",
         "/api/rakuma/shop_items",
@@ -405,6 +418,27 @@ def test_rakuma_search_rejects_rakuten_only_sort(client):
     assert response.status_code == 422
 
 
+def test_rakuma_categories_accepts_empty_body_for_top_level(client, rakuma_stub):
+    """不传 category_id 时取顶层分类，不应因缺参数被拦下"""
+    response = client.post("/api/rakuma/categories", json={}, headers=AUTH)
+    assert response.status_code == 200
+    assert rakuma_stub.category_payload.category_id is None
+    assert rakuma_stub.category_payload.include_descendants is False
+    assert response.json()["data"]["total_count"] == 1686
+
+
+def test_rakuma_categories_passes_options_through(client, rakuma_stub):
+    response = client.post(
+        "/api/rakuma/categories",
+        json={"category_id": "10007", "include_descendants": True},
+        headers=AUTH,
+    )
+    assert response.status_code == 200
+    assert rakuma_stub.category_payload.category_id == "10007"
+    assert rakuma_stub.category_payload.include_descendants is True
+    assert response.json()["data"]["children"][0]["category_id"] == "786"
+
+
 def test_rakuma_item_detail_accepts_item_id(client, rakuma_stub):
     response = client.post("/api/rakuma/item_detail", json={"item_id": "abc"}, headers=AUTH)
     assert response.status_code == 200