feat: tournament rake, percentage-based prizes, and finish position fixes

- Add tournament_rake_percentage field to GameConfig (house share of entry fees)
- Convert prize structure from absolute amounts to percentages of prize pool
- Fix finish position calculation for tournament eliminations (was inverted)
- Add batch bustout processing for multi-table tournaments (shared positions)
- Add max_rebuys field and rebuy_count tracking on Seat
- Add PrizeStructure::with_rake() and rake_amount field
- Accumulate stats across tournament series (hands, rake, profit)
- Add best_finish and prize_won fields to PlayerStats
- Replace floating-point prize math with integer arithmetic (chip conservation)
- Add comprehensive tests for prize distribution and finish positions
- Update config examples to use percentage-based prizes with rake
- Add ARCHITECTURE_TOURNAMENT_RAKE.md documentation

holdem_core/examples/configs/cash_game.toml

@@ -15,9 +15,12 @@ num_hands = 10000
 # reset_bankroll_each_hand = false
 # bankroll_refill_threshold = 1000  # Refill when stack <= 1000
 
-# Auto-rebuy: when enabled, players whose stack drops below half the
+# Auto-rebuy: when enabled, players whose stack drops below 25% of the
 # starting_chips are automatically topped back up to starting_chips.
+# Configure the threshold via rebuy_threshold_percentage (default: 25).
+# max_rebuys limits how many times a player can rebuy (0 = unlimited).
 auto_rebuy = true
+max_rebuys = 0  # 0 = unlimited rebuys
 
 # Randomize seat assignments before each hand (optional, defaults to false).
 randomize_seats = true

holdem_core/examples/configs/mtt_10_tables.toml

@@ -7,7 +7,8 @@
 # (last player standing wins).
 #
 # 100 tournaments are run with aggregate statistics tracked by player name.
-# Entry fee: 5 per tournament. Final table prizes: 200, 100, 50, 30, 20, 10, 10, 10, 10, 10.
+# Entry fee: 5 per tournament. House keeps 5% rake.
+# Prizes are percentages of the remaining prize pool.
 
 [game]
 game_type = "MultiTableTournament"
@@ -22,15 +23,20 @@ num_blind_levels = 20
 randomize_seats = true
 num_tournaments = 100
 
+# Tournament rake: house keeps 5% of entry fees.
+# With 100 players: total_entry_fees = 500, house_rake = 25, prize_pool = 475
+tournament_rake_percentage = 5
+
+# ---------------------------------------------------------------------------
+# Prize structure as percentages of prize pool (100 players × $5 = $500 total,
+# minus 5% rake = $475 prize pool)
+# ---------------------------------------------------------------------------
+prizes = [40, 20, 10, 6, 4, 4, 4, 4, 4, 4]
+
 [game.bet_limit]
 type = "no_limit"
 min_raise = 20
 
-# ---------------------------------------------------------------------------
-# Prize structure (100 players × $5 buy-in = $500 prize pool, top 10 paid)
-# ---------------------------------------------------------------------------
-prizes = [200, 100, 50, 30, 20, 10, 10, 10, 10, 10]
-
 # ---------------------------------------------------------------------------
 # Blind levels (extended to 12 levels)
 # ---------------------------------------------------------------------------

holdem_core/examples/configs/sng_tournament.toml

@@ -6,7 +6,11 @@ buy_in = 11
 randomize_seats = true
 num_tournaments = 100
 
-# Custom prize structure in chip amounts: 1st=5, 2nd=3, 3rd=2
+# Tournament rake: house keeps 10% of entry fees.
+# With 10 players: total_entry_fees = 110, house_rake = 11, prize_pool = 99
+tournament_rake_percentage = 10
+
+# Custom prize structure as percentages of prize pool: 1st=50%, 2nd=30%, 3rd=20%
 prizes = [50, 30, 20]
 
 [game.bet_limit]