Per-type expiry tail on the shopfloor board, and a 2x2 recertification block

plugins/notifications/models/notification.py

@@ -75,6 +75,14 @@ class NotificationType(db.Model):
     showemployeephoto = db.Column(db.Boolean, default=False)
     displaystyle = db.Column(db.String(20), default='standard')
 
+    # Minutes a card stays on the shopfloor board AFTER its end time, shown as
+    # RESOLVED. 0 (the default) means it leaves the board the moment it ends,
+    # which is what a reader expects from an end time. A type whose cards are
+    # worth acknowledging after the fact - an incident that just cleared - can
+    # opt into a tail.
+    gracewindowminutes = db.Column(db.Integer, nullable=False,
+                                   server_default='0', default=0)
+
     def __repr__(self):
         return f"<NotificationType {self.typename}>"
 
@@ -91,7 +99,8 @@ class NotificationType(db.Model):
             'expiryminute': self.expiryminute if self.expiryminute is not None else 0,
             'splitperemployee': bool(self.splitperemployee),
             'showemployeephoto': bool(self.showemployeephoto),
-            'displaystyle': self.displaystyle or 'standard'
+            'displaystyle': self.displaystyle or 'standard',
+            'gracewindowminutes': int(self.gracewindowminutes or 0)
         }