로스트 시티 클래식 코어 이식

맥락:
- 새 레포의 첫 범위를 RL 없는 Lost Cities classic 게임 구현으로 잡았다.
- 기존 tier0-3 실험 축은 제거하고 classic 5-expedition 룰을 기본값으로 둔다.

변경:
- games/classic 아래에 Cython 게임 엔진, env, bots, backend 경계, Rust core와 proto schema를 이식했다.
- setuptools/Cython 빌드 설정과 package data, README, classic port notes를 추가했다.
- 룰, 점수, 마스크, env, canonical state, bot, Rust parity 테스트를 새 경로로 가져왔다.

확인:
- uv run pytest tests/games/classic
- uv run lost-cities-classic

tests/games/classic/test_masks.py

@@ -0,0 +1,58 @@
+from coolrl_lost_cities.games.classic.bots import RandomBot
+from coolrl_lost_cities.games.classic.game import Card, GameState, LostCitiesConfig
+
+
+def test_legal_mask_has_action_in_nonterminal_phases() -> None:
+    state = GameState.new_game(LostCitiesConfig(seed=3))
+    while not state.terminal:
+        assert any(state.legal_mask())
+        action = RandomBot(11).act(state)
+        state.apply_action(action)
+
+
+def test_empty_hand_slots_are_masked() -> None:
+    state = GameState.empty(LostCitiesConfig())
+    state.hands[0] = [Card(0, 1)]
+    mask = state.legal_card_mask()
+    assert mask[0] is True
+    assert mask[1] is True
+    assert all(value is False for value in mask[2:])
+
+
+def test_empty_discard_pile_draw_is_illegal() -> None:
+    state = GameState.empty(LostCitiesConfig())
+    state.phase = "draw"
+    state.deck = [Card(0, 1)]
+    mask = state.legal_draw_mask()
+    assert mask[0] is True
+    assert all(mask[1 + color] is False for color in range(state.config.n_colors))
+
+
+def test_unified_legal_mask_has_fixed_shape_across_phases() -> None:
+    config = LostCitiesConfig()
+    state = GameState.new_game(config, seed=1)
+    assert len(state.unified_legal_mask()) == config.action_size
+
+    action = next(index for index, legal in enumerate(state.legal_mask()) if legal)
+    state.apply_action(action)
+
+    mask = state.unified_legal_mask()
+    assert state.phase == "draw"
+    assert len(mask) == config.action_size
+    assert all(value is False for value in mask[:config.card_action_size])
+    assert any(mask[config.card_action_size:])
+
+
+def test_random_fuzz_invariants() -> None:
+    config = LostCitiesConfig(n_colors=3, n_ranks=5, n_handshakes=1, hand_size=5)
+    bot = RandomBot(99)
+    for seed in range(1000):
+        state = GameState.new_game(config, seed=seed)
+        steps = 0
+        while not state.terminal:
+            mask = state.legal_mask()
+            assert any(mask)
+            action = bot.act(state)
+            state.apply_action(action)
+            steps += 1
+            assert steps < 1000