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.

src/McRFPy_API.cpp

@@ -87,12 +87,12 @@ PyObject* PyInit_mcrfpy()
     auto t = pytypes[i];
     while (t != nullptr)
     {
-        std::cout << "Registering type: " << t->tp_name << std::endl;
+        //std::cout << "Registering type: " << t->tp_name << std::endl;
         if (PyType_Ready(t) < 0) {
             std::cout << "ERROR: PyType_Ready failed for " << t->tp_name << std::endl;
             return NULL;
         }
-        std::cout << "  tp_alloc after PyType_Ready: " << (void*)t->tp_alloc << std::endl;
+        //std::cout << "  tp_alloc after PyType_Ready: " << (void*)t->tp_alloc << std::endl;
         PyModule_AddType(m, t);
         i++;
         t = pytypes[i];
@@ -316,7 +316,9 @@ void McRFPy_API::executeScript(std::string filename)
 {
     FILE* PScriptFile = fopen(filename.c_str(), "r");
     if(PScriptFile) {
+        std::cout << "Before PyRun_SimpleFile" << std::endl;
         PyRun_SimpleFile(PScriptFile, filename.c_str());
+        std::cout << "After PyRun_SimpleFile" << std::endl;
         fclose(PScriptFile);
     }
 }