Contract 6.24.0

The collection tools, after the Elixir Gym's first run on them (feedback #114-#116).

• Collections carry synced_from: the live board a collection's membership is re-synced from daily, or null for a curated one. A board collection says it follows the board and is not a fixed cohort, and its description says so. A collection segment on the meta tools and cards_card says it applies the membership as of the call (#116).
• collections_get says how its rows are ordered and what they are not: Trophy Road trophies, not a Path of Legends rating or the board's rank, with rankings_players / rankings_clans for the board's order. It also defines open_members, which is the clan's member count, not open places (#114, #115).
• collections_browse, collections_get and collections_edit publish their outputSchema (#115).

Additive.