Contract 6.30.0

The badge tools, after the Elixir Gym's second run on them (feedback #144-#146).

• badges_rarity quotes each versioned pair (RoyalTournamentRank / RoyalTournamentRank_v2) as distinct players holding either, and how many hold both. It used to say to add the two rows, which double-counted a player who holds both. badges_holders names the other half of a pair and its count in the same population, so "Royal Tournament Rank" no longer reads as 0 of the top 100 when 73 hold the _v2 (#144).
• On the corpus segment, a note says what players_considered counts: every player whose profile the record has read, not only the players recorded now. A holder's clan_tag is described as the clan at observed_at (#145).
• A misspelled badge label is refused with the closest badges by edit distance ("Valkyrie Mastry" suggests MasteryValkyrie), and every miss says exactly (#146).

Notes and refusal text; no value changes.