Fixed
- A reward without an icon no longer shows the word "null" after you edit it (#789). The edit form always sends every field, sending the empty ones as nothing at all, and the route could not tell "leave this alone" apart from "clear this" - so it stored the text "null" as the icon. Changing the price of a reward was enough to trigger it, and clearing a description had the same effect. Rewards that already carry the stray text are cleaned up on upgrade, including the copy of the icon kept in the redemption history; a description that merely contains the word is left alone.