feat!: breaking change - OpenRouter models are now read from conf/openrouter_models.json while Custom / Self-hosted models are read from conf/custom_models.json

feat: Azure OpenAI / Azure AI Foundry support. Models should be defined in conf/azure_models.json (or a custom path). See .env.example for environment variables or see readme. https://github.com/BeehiveInnovations/zen-mcp-server/issues/265

feat: OpenRouter / Custom Models / Azure can separately also use custom config paths now (see .env.example )

refactor: Model registry class made abstract, OpenRouter / Custom Provider / Azure OpenAI now subclass these

refactor: breaking change: `is_custom` property has been removed from model_capabilities.py (and thus custom_models.json) given each models are now read from separate configuration files

tests/test_xai_provider.py

@@ -166,8 +166,10 @@ class TestXAIProvider:
         """Test model restrictions functionality."""
         # Clear cached restriction service
         import utils.model_restrictions
+        from providers.registry import ModelProviderRegistry
 
         utils.model_restrictions._restriction_service = None
+        ModelProviderRegistry.reset_for_testing()
 
         provider = XAIModelProvider("test-key")
 
@@ -187,8 +189,10 @@ class TestXAIProvider:
         """Test multiple models in restrictions."""
         # Clear cached restriction service
         import utils.model_restrictions
+        from providers.registry import ModelProviderRegistry
 
         utils.model_restrictions._restriction_service = None
+        ModelProviderRegistry.reset_for_testing()
 
         provider = XAIModelProvider("test-key")