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/automation_screenshot_test_simple.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+"""Simple test for mcrfpy.automation.screenshot()"""
+import mcrfpy
+from mcrfpy import automation
+import os
+import sys
+
+# Create a simple scene
+mcrfpy.createScene("test")
+mcrfpy.setScene("test")
+
+# Take a screenshot immediately
+try:
+    filename = "test_screenshot.png"
+    result = automation.screenshot(filename)
+    print(f"Screenshot result: {result}")
+    
+    # Check if file exists
+    if os.path.exists(filename):
+        size = os.path.getsize(filename)
+        print(f"PASS - Screenshot saved: {filename} ({size} bytes)")
+    else:
+        print(f"FAIL - Screenshot file not created: {filename}")
+except Exception as e:
+    print(f"FAIL - Screenshot error: {e}")
+    import traceback
+    traceback.print_exc()
+
+# Exit immediately
+sys.exit(0)