Revert "Restructure {reasoning_gym, tests}/{core, exercises, curricula}"

This reverts commit 10dbb374b0.

reasoning_gym/games/__init__.py

@@ -0,0 +1,29 @@
+"""
+Game tasks for training reasoning capabilities:
+- Board games
+- Puzzle games
+- Strategy games
+- Simulation games
+"""
+
+from .countdown import CountdownConfig, CountdownDataset
+from .game_of_life import GameOfLifeConfig, GameOfLifeDataset
+from .maze import MazeConfig, MazeDataset
+from .mini_sudoku import MiniSudokuConfig, MiniSudokuDataset
+from .sudoku import SudokuConfig, SudokuDataset
+from .tower_of_hanoi import HanoiConfig, HanoiDataset
+
+__all__ = [
+    "CountdownConfig",
+    "CountdownDataset",
+    "MiniSudokuConfig",
+    "MiniSudokuDataset",
+    "SudokuConfig",
+    "SudokuDataset",
+    "MazeConfig",
+    "MazeDataset",
+    "GameOfLifeConfig",
+    "GameOfLifeDataset",
+    "HanoiConfig",
+    "HanoiDataset",
+]