refactor(server): 移除鉴权并归档遗留路由至 legacy/

- 删除 auth.py 与 deps.py，各路由去除 get_current_user 依赖
- collection.py 更名为 materials.py，冻结链路（ozon/publish/shops/categories）移入 legacy/
- 扩展默认生图服务端口并入 8800 并自动迁移旧配置，水印默认文案改为 Panda Store
- 新增 docs/v2.1/backend-structure.md 后端结构盘点文档

server/legacy/schemas/shop.py

@@ -0,0 +1,34 @@
+"""店铺（Ozon 凭证）请求/响应模型。"""
+# ⚠️ 冻结代码（Ozon API 直传链路）：保留不维护，V2.1 起接口保留但不再投入。
+from __future__ import annotations
+
+from datetime import datetime
+from uuid import UUID
+
+from pydantic import BaseModel, ConfigDict
+
+
+class ShopCreate(BaseModel):
+    name: str
+    client_id: str
+    api_key: str
+    currency_code: str = "CNY"
+
+
+class ShopUpdate(BaseModel):
+    name: str | None = None
+    client_id: str | None = None
+    api_key: str | None = None
+    currency_code: str | None = None
+
+
+class ShopListItem(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: UUID
+    name: str
+    currency_code: str
+    status: str
+    client_id_masked: str = ""  # 打码尾号
+    last_checked_at: datetime | None = None
+    created_at: datetime