Fix --exec interactive prompt bug and create comprehensive test suite

Major fixes:
- Fixed --exec entering Python REPL instead of game loop
- Resolved screenshot transparency issue (requires timer callbacks)
- Added debug output to trace Python initialization

Test suite created:
- 13 comprehensive tests covering all Python-exposed methods
- Tests use timer callback pattern for proper game loop interaction
- Discovered multiple critical bugs and missing features

Critical bugs found:
- Grid class segfaults on instantiation (blocks all Grid functionality)
- Issue #78 confirmed: Middle mouse click sends 'C' keyboard event
- Entity property setters have argument parsing errors
- Sprite texture setter returns improper error
- keypressScene() segfaults on non-callable arguments

Documentation updates:
- Updated CLAUDE.md with testing guidelines and TDD practices
- Created test reports documenting all findings
- Updated ROADMAP.md with test results and new priorities

The Grid segfault is now the highest priority as it blocks all Grid-based functionality.

tests/api_createScene_test.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+"""Test for mcrfpy.createScene() method"""
+import mcrfpy
+
+def test_createScene():
+    """Test creating a new scene"""
+    # Test creating scenes
+    test_scenes = ["test_scene1", "test_scene2", "special_chars_!@#"]
+    
+    for scene_name in test_scenes:
+        try:
+            mcrfpy.createScene(scene_name)
+            print(f"✓ Created scene: {scene_name}")
+        except Exception as e:
+            print(f"✗ Failed to create scene {scene_name}: {e}")
+            return
+    
+    # Try to set scene to verify it was created
+    try:
+        mcrfpy.setScene("test_scene1")
+        current = mcrfpy.currentScene()
+        if current == "test_scene1":
+            print("✓ Scene switching works correctly")
+        else:
+            print(f"✗ Scene switch failed: expected 'test_scene1', got '{current}'")
+    except Exception as e:
+        print(f"✗ Scene switching error: {e}")
+    
+    print("PASS")
+
+# Run test immediately
+print("Running createScene test...")
+test_createScene()
+print("Test completed.")