Native support for xAI Grok3

Model shorthand mapping related fixes
Comprehensive auto-mode related tests

simulator_tests/__init__.py

@@ -24,6 +24,7 @@ from .test_redis_validation import RedisValidationTest
 from .test_refactor_validation import RefactorValidationTest
 from .test_testgen_validation import TestGenValidationTest
 from .test_token_allocation_validation import TokenAllocationValidationTest
+from .test_xai_models import XAIModelsTest
 
 # Test registry for dynamic loading
 TEST_REGISTRY = {
@@ -44,6 +45,7 @@ TEST_REGISTRY = {
     "testgen_validation": TestGenValidationTest,
     "refactor_validation": RefactorValidationTest,
     "conversation_chain_validation": ConversationChainValidationTest,
+    "xai_models": XAIModelsTest,
     # "o3_pro_expensive": O3ProExpensiveTest,  # COMMENTED OUT - too expensive to run by default
 }
 
@@ -67,5 +69,6 @@ __all__ = [
     "TestGenValidationTest",
     "RefactorValidationTest",
     "ConversationChainValidationTest",
+    "XAIModelsTest",
     "TEST_REGISTRY",
 ]