chore: update model lists and defaults to GPT-5.4 family

tradingagents/default_config.py

@@ -9,8 +9,8 @@ DEFAULT_CONFIG = {
     ),
     # LLM settings
     "llm_provider": "openai",
-    "deep_think_llm": "gpt-5.2",
-    "quick_think_llm": "gpt-5-mini",
+    "deep_think_llm": "gpt-5.4",
+    "quick_think_llm": "gpt-5.4-mini",
     "backend_url": "https://api.openai.com/v1",
     # Provider-specific thinking configuration
     "google_thinking_level": None,      # "high", "minimal", etc.