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/models/shop.py

@@ -0,0 +1,31 @@
+"""Ozon 店铺（Client-Id / Api-Key 加密落库）。"""
+# ⚠️ 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
+
+import uuid
+from datetime import datetime
+
+from sqlalchemy import DateTime, Enum, String, Uuid, func
+from sqlalchemy.orm import Mapped, mapped_column
+
+from db import Base
+from models.enums import ShopStatus
+
+
+class Shop(Base):
+    __tablename__ = "shops"
+
+    id: Mapped[uuid.UUID] = mapped_column(Uuid(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    user_id: Mapped[uuid.UUID | None] = mapped_column(Uuid(as_uuid=True), nullable=True)  # 预留多用户
+    name: Mapped[str] = mapped_column(String(128), nullable=False)
+    client_id_enc: Mapped[str] = mapped_column(String(1024), nullable=False)  # AES-GCM 密文
+    api_key_enc: Mapped[str] = mapped_column(String(1024), nullable=False)
+    currency_code: Mapped[str] = mapped_column(String(3), default="RUB", server_default="RUB")
+    status: Mapped[ShopStatus] = mapped_column(
+        Enum(ShopStatus, native_enum=False, length=16), default=ShopStatus.active
+    )
+    last_checked_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), server_default=func.now())
+    updated_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), server_default=func.now(), onupdate=func.now()
+    )