Fix the bots' corner bias; settle seat order and RULES v0.9 (6.2, 6.8)

Bots now pick their start square and break path ties in their own
corner's frame; the absolute tie-break made corners 1 and 2 win 25-28%.
With that fixed, seat order is within target at 4 players, and a +1
stripe first-player bonus (new switch) gains only ~1 point, so no
compensation. RULES.md v0.9 lists the tested alternatives; the plan has
the 6.8 consolidation run and the seat-order study.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/test_bots.py

@@ -3,9 +3,9 @@
 import random
 
 import pytest
-from scripted import make_game, put
+from scripted import fixture_board, make_game, put
 
-from dojo.board import Board, Pos
+from dojo.board import Board, Pos, rotate
 from dojo.bots import (
     AGGRESSIVE,
     BALANCED,
@@ -15,7 +15,9 @@ from dojo.bots import (
     HeuristicAgent,
     Profile,
     RandomAgent,
+    own_frame,
     series_probability,
+    start_square,
     win_probability,
 )
 from dojo.engine import Agent, FightView, Game, RandomSource
@@ -73,9 +75,29 @@ def test_heuristic_sees_no_opponent_to_fight_in_round_one() -> None:
     put(game, 1, TATAMI, track=3)
 
     # In round 2 the aggressive bot picks the fight (test_profiles_differ_on_an_even_fight).
-    choice = HeuristicAgent(AGGRESSIVE).choose_path(game.view(0), [(Pos(5, 3),), (TATAMI,)])
+    # Two plain Tatami tie; the tie goes to the lower square in the bot's frame, (4, 2).
+    choice = HeuristicAgent(AGGRESSIVE).choose_path(game.view(0), [(TATAMI,), (Pos(4, 2),)])
 
-    assert choice == (Pos(5, 3),)
+    assert choice == (Pos(4, 2),)
+
+
+def test_bots_start_from_the_same_square_of_every_safe_room() -> None:
+    board = fixture_board()
+
+    assert len({own_frame(start_square(board, corner), corner) for corner in range(4)}) == 1
+
+
+def test_tied_paths_are_chosen_alike_from_every_corner() -> None:
+    game, _, _ = make_game(players=4)
+    agent = HeuristicAgent(BALANCED)
+    chosen = set()
+    for seat, player in enumerate(game.players):
+        player.position = rotate(Pos(4, 3), player.corner)
+        tatami = [(rotate(square, player.corner),) for square in (Pos(5, 3), Pos(3, 3), Pos(4, 2))]
+        choice = agent.choose_path(game.view(seat), tatami)
+        chosen.add(own_frame(choice[0], player.corner))
+
+    assert chosen == {Pos(3, 3)}
 
 
 def test_brown_heuristic_takes_the_exam_when_it_can() -> None: