```

feat(auth): 添加用户权限获取接口并完善JWT令牌角色信息

- 在JWT令牌中添加用户角色信息
- 新增get_my_permissions接口用于获取当前用户权限码列表
- 重构认证回调逻辑，增加错误日志记录
- 更新用户信息获取接口使用Authorization头验证
```

backend/app/models/device.py

@@ -13,6 +13,7 @@ class OLTDevice(Base):
     username = Column(String(100), nullable=False)
     password = Column(Text, nullable=False)
     slot_command = Column(String(50), nullable=False)
+    region = Column(String(100), index=True)
     location = Column(String(200))
     description = Column(Text)
     created_at = Column(TIMESTAMP, server_default=func.now())
@@ -72,6 +73,18 @@ class DuplicateMac(Base):
     last_seen_at = Column(TIMESTAMP, server_default=func.now(), onupdate=func.now())
 
 
+class DeviceDailySnapshot(Base):
+    """设备每日状态快照（用于趋势图，避免全量扫描历史表）"""
+    __tablename__ = "device_daily_snapshots"
+
+    id = Column(BigInteger, primary_key=True, index=True)
+    snapshot_date = Column(String(10), nullable=False, index=True)  # YYYY-MM-DD
+    total = Column(Integer, nullable=False, default=0)
+    online = Column(Integer, nullable=False, default=0)
+    offline = Column(Integer, nullable=False, default=0)
+    created_at = Column(TIMESTAMP, server_default=func.now())
+
+
 class NewDevice(Base):
     """新发现设备（OLT 扫描到但尚未补全信息的设备）"""
     __tablename__ = "new_devices"
@@ -80,3 +93,18 @@ class NewDevice(Base):
     onu_device_id = Column(BigInteger, ForeignKey("onu_devices.id"), nullable=False, unique=True)
     olt_id = Column(BigInteger, ForeignKey("olt_devices.id"), nullable=False)
     discovered_at = Column(TIMESTAMP, server_default=func.now())
+
+
+class DeviceReplacement(Base):
+    """设备更换记录"""
+    __tablename__ = "device_replacements"
+
+    id = Column(BigInteger, primary_key=True, index=True)
+    onu_device_id = Column(BigInteger, ForeignKey("onu_devices.id"), nullable=False, index=True)
+    old_mac = Column(String(17), nullable=False)
+    new_mac = Column(String(17), nullable=False)
+    reason = Column(Text)
+    operator_id = Column(String(100))   # 操作人 user_id
+    operator_name = Column(String(100))
+    replaced_at = Column(TIMESTAMP, nullable=False, server_default=func.now())
+    created_at = Column(TIMESTAMP, server_default=func.now())