feat(weibo): 增加账号分配与客服数据隔离

web/backend/models.py

@@ -934,6 +934,11 @@ class WeiboAccount(Base):
         String(256), nullable=False, default="", server_default=""
     )
     activity: Mapped[str] = mapped_column(String(64), default="")
+    assigned_to: Mapped[int | None] = mapped_column(
+        ForeignKey("users.id", ondelete="SET NULL"),
+        nullable=True,
+        index=True,
+    )
 
     is_enabled: Mapped[bool] = mapped_column(
         Boolean, nullable=False, default=True, server_default="1", index=True
@@ -960,6 +965,11 @@ class WeiboAccount(Base):
         UTCDateTime, default=_utcnow, onupdate=_utcnow
     )
 
+    assigned_user: Mapped[User | None] = relationship(
+        "User",
+        foreign_keys=[assigned_to],
+    )
+
 
 class WeiboWorkbenchAccount(Base):
     """用户个人微博工作台中的账号选择。"""