Remediate the 2026-09-03 feature-test findings

plugins/usb/models/usb_device.py

@@ -128,6 +128,13 @@ class USBCheckout(BaseModel):
     # Checkout details
     checkouttime = db.Column(db.DateTime, nullable=False, default=_utcnow)
     checkintime = db.Column(db.DateTime, nullable=True)
+    # WHO handed it back. Not always the holder: returning for a colleague is a
+    # supported flow, and recording the check-in against the holder named
+    # somebody who was not there. See migration usb0004checkinidentity.
+    checkinsso = db.Column(db.String(20), nullable=True,
+                           comment='SSO of whoever returned it')
+    checkinname = db.Column(db.String(100), nullable=True,
+                            comment='Name of whoever returned it')
 
     # Metadata
     checkoutreason = db.Column(db.Text, nullable=True, comment='Reason for checkout')