chore: update model lists, bump to v0.2.1, fix package build

- OpenAI: add GPT-5.4, GPT-5.4 Pro; remove o-series and legacy GPT-4o
- Anthropic: add Claude Opus 4.6, Sonnet 4.6; remove legacy 4.1/4.0/3.x
- Google: add Gemini 3.1 Pro, 3.1 Flash Lite; remove deprecated
  gemini-3-pro-preview and Gemini 2.0 series
- xAI: clean up model list to match current API
- Simplify UnifiedChatOpenAI GPT-5 temperature handling
- Add missing tradingagents/__init__.py (fixes pip install building)

tradingagents/llm_clients/validators.py

@@ -6,59 +6,44 @@ Let LLM providers use their own defaults for unspecified params.
 
 VALID_MODELS = {
     "openai": [
-        # GPT-5 series (2025)
+        # GPT-5 series
+        "gpt-5.4-pro",
+        "gpt-5.4",
         "gpt-5.2",
         "gpt-5.1",
         "gpt-5",
         "gpt-5-mini",
         "gpt-5-nano",
-        # GPT-4.1 series (2025)
+        # GPT-4.1 series
         "gpt-4.1",
         "gpt-4.1-mini",
         "gpt-4.1-nano",
-        # o-series reasoning models
-        "o4-mini",
-        "o3",
-        "o3-mini",
-        "o1",
-        "o1-preview",
-        # GPT-4o series (legacy but still supported)
-        "gpt-4o",
-        "gpt-4o-mini",
     ],
     "anthropic": [
-        # Claude 4.5 series (2025)
+        # Claude 4.6 series (latest)
+        "claude-opus-4-6",
+        "claude-sonnet-4-6",
+        # Claude 4.5 series
         "claude-opus-4-5",
         "claude-sonnet-4-5",
         "claude-haiku-4-5",
-        # Claude 4.x series
-        "claude-opus-4-1-20250805",
-        "claude-sonnet-4-20250514",
-        # Claude 3.7 series
-        "claude-3-7-sonnet-20250219",
-        # Claude 3.5 series (legacy)
-        "claude-3-5-haiku-20241022",
-        "claude-3-5-sonnet-20241022",
     ],
     "google": [
+        # Gemini 3.1 series (preview)
+        "gemini-3.1-pro-preview",
+        "gemini-3.1-flash-lite-preview",
         # Gemini 3 series (preview)
-        "gemini-3-pro-preview",
         "gemini-3-flash-preview",
         # Gemini 2.5 series
         "gemini-2.5-pro",
         "gemini-2.5-flash",
         "gemini-2.5-flash-lite",
-        # Gemini 2.0 series
-        "gemini-2.0-flash",
-        "gemini-2.0-flash-lite",
     ],
     "xai": [
         # Grok 4.1 series
-        "grok-4-1-fast",
         "grok-4-1-fast-reasoning",
         "grok-4-1-fast-non-reasoning",
         # Grok 4 series
-        "grok-4",
         "grok-4-0709",
         "grok-4-fast-reasoning",
         "grok-4-fast-non-reasoning",