Contract 6.17.0

Event content is its own mode group, and it no longer informs the meta. Game modes are played as different games, and Elixir was pooling them.

• event joins the mode groups, decided by the API's own eventTag rather than by the battle type. type: trail carries one on 100% of 123,562 recorded battles and every permanent format carries one on 0%, so the tag - not the type, not the mode's name - is what marks time-bound content. trail used to fold into casual, which filed the reworked Seasonal Trophy Road as casual play and pooled a fortnight's 2v2 tournament with ordinary friendlies. mode: 'event' selects it; every other mode now excludes it.
• The meta population EXCLUDES event content and decks the player did not choose (deck_selection outside collection and warDeckPick: eventDeck, draft, draftCompetitive, pick, quadDeckPick, predefined). A Seasonal Arena II deck is floored at Level 15 - its recorded decks average 15.87 against 13.67 on Trophy Road - and a drafted deck is not a deck anyone chose, so a win rate over either measures the format. Both remain fully readable through battles_query and a player's own record.
• event is a FILTER, never a population: one event is not another. trail+TeamVsTeam alone has carried ten distinct event tags, and a rate over event content must key on context.event_tag itself.

A player's own battle counts are unchanged in total; battles that used to read casual now read event. Meta and deck statistics change: they were counting populations that do not describe the meta.