feat(rewards): add completed, background and banner effect items

readme.md

@@ -63,7 +63,8 @@ To Be Played is split into three repositories:
   snapshots, once per user, kind and game (`ref`). Rules and numbers: `RewardRules`; a Steam finish needs playtime and one
   proof of fresh play (ending achievement or playtime around the finish, or half of the IGDB time played since the finish; old history pays nothing). The month bonus needs a finished game in that month. Games added by hand pay 15 for
   a finish, at most 3 per ISO week. The settle takes a per-user advisory lock. V26 also pays a one-time starter grant
-  for finishes from before the status log. Shop: a whitelist of 8 looks (`ShopItem`); a `BUY` row proves ownership,
+  for finishes from before the status log. Shop: a whitelist of 28 looks (`ShopItem`) in seven slots, including animated completed effects, page backgrounds and banner
+  backgrounds (V27 widens `reward_equipped.slot`); a `BUY` row proves ownership,
   `reward_equipped` holds what is worn. A platform admin owns every item (the role of the login token, or the `role`
   claim of the profile ticket for visitors).
 - **Wishlist**: synced from Steam with store price and discount.