Contract 6.21.0

The battle tools, after the Elixir Gym's first run on them (feedback #95-#100).

• A duel's outcome is the games won, first to two, not the summed crowns (#95). A duel won 0-3, 1-0, 1-0 had been recorded as a loss at 2 crowns to 3, and 7 of one player's 70 duels were wrong in this way, some of them as false draws. Ingest decides it from the rounds, and the duels recorded before were recomputed along with their daily rollups.
• A duel's elixir.leaked is the sum across its games, as the note and schema already said (#96). It had been the final game's counter.
• me.vs gains tower_level, the tower troop's level edge. A note fires when the towers started unequal, because vs.tower_hp then includes the starting-hitpoint gap as well as the damage. vs is null on boat battles (#97).
• On river race rows a note says vs.starting_trophies is not what matchmaking paired: war draws from the racing clans (#98).
• battles_performance.trophy_floor.floor is the floor the player stood on most recently, with its own counts. The new floors[] lists every floor the window stood on, and the note names each (#99). Before this, floor was the lowest floor and every free loss was put on it.
• tower_hp.princess is [0, 0] when both princess towers fell, as the docs promise (#100). The key had been missing.

Additive fields (vs.tower_level, trophy_floor.floors); corrected values (duel outcome and leak, trophy_floor.floor on a multi-floor window).