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

plugins/notifications/migrations/versions/0003_gracewindowminutes.py

@@ -0,0 +1,47 @@
+"""Add notificationtypes.gracewindowminutes (post-expiry tail on the board).
+
+The shopfloor feed kept every ended notification on the board for a hardcoded
+30 minutes, flagged resolved. A card with an 8:00 end time therefore sat there
+until 8:30, and in the carousel/grid/banner sections it did so with no visual
+sign it had ended at all. The tail is now per type and defaults to 0, so an end
+time means what it says; a type that wants an acknowledged tail opts in.
+
+Idempotent; downgrade drops the column.
+
+Revision ID: notifications0003grace
+Revises: notifications0002buidx
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+revision = 'notifications0003grace'
+down_revision = 'notifications0002buidx'
+branch_labels = None
+depends_on = None
+
+_TABLE = 'notificationtypes'
+_COLUMN = 'gracewindowminutes'
+
+
+def _column_names(insp, table):
+    return {c['name'] for c in insp.get_columns(table)}
+
+
+def upgrade():
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    if _TABLE not in insp.get_table_names():
+        return
+    if _COLUMN not in _column_names(insp, _TABLE):
+        op.add_column(_TABLE, sa.Column(_COLUMN, sa.Integer(), nullable=False,
+                                        server_default='0'))
+
+
+def downgrade():
+    bind = op.get_bind()
+    insp = sa.inspect(bind)
+    if _TABLE not in insp.get_table_names():
+        return
+    if _COLUMN in _column_names(insp, _TABLE):
+        op.drop_column(_TABLE, _COLUMN)