Phone audit: leaderboard flooded with 9 consecutive identical 'stolen_bases U0.5
45% B' rows. New shared lib/playerGrouping (dedupeLeaders + groupIntoLadders,
name-key aware, 7 unit tests): ONE row per (player, market family) keeping the
best-ranked, then a per-market cap (4) so no single prop type floods the board.
Applied to ExploreHub. Ledger cards + Consensus grouping follow in P0-3b/c using
the same lib.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
