Add encouraging message about powerful models to schema in case it's not on Opus 4 or above

OPENROUTER_ALLOWED_MODELS environment variable support to further limit the models to allow from within Claude. This will put a limit on top of even the ones listed in custom_models.json

utils/model_restrictions.py

@@ -9,10 +9,12 @@ standardization purposes.
 Environment Variables:
 - OPENAI_ALLOWED_MODELS: Comma-separated list of allowed OpenAI models
 - GOOGLE_ALLOWED_MODELS: Comma-separated list of allowed Gemini models
+- OPENROUTER_ALLOWED_MODELS: Comma-separated list of allowed OpenRouter models
 
 Example:
     OPENAI_ALLOWED_MODELS=o3-mini,o4-mini
     GOOGLE_ALLOWED_MODELS=flash
+    OPENROUTER_ALLOWED_MODELS=opus,sonnet,mistral
 """
 
 import logging
@@ -38,6 +40,7 @@ class ModelRestrictionService:
     ENV_VARS = {
         ProviderType.OPENAI: "OPENAI_ALLOWED_MODELS",
         ProviderType.GOOGLE: "GOOGLE_ALLOWED_MODELS",
+        ProviderType.OPENROUTER: "OPENROUTER_ALLOWED_MODELS",
     }
 
     def __init__(self):