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

providers/custom_registry.py

@@ -0,0 +1,26 @@
+"""Registry for models exposed via custom (local) OpenAI-compatible endpoints."""
+
+from __future__ import annotations
+
+from .model_registry_base import CAPABILITY_FIELD_NAMES, CapabilityModelRegistry
+from .shared import ModelCapabilities, ProviderType
+
+
+class CustomEndpointModelRegistry(CapabilityModelRegistry):
+    def __init__(self, config_path: str | None = None) -> None:
+        super().__init__(
+            env_var_name="CUSTOM_MODELS_CONFIG_PATH",
+            default_filename="custom_models.json",
+            provider=ProviderType.CUSTOM,
+            friendly_prefix="Custom ({model})",
+            config_path=config_path,
+        )
+        self.reload()
+
+    def _finalise_entry(self, entry: dict) -> tuple[ModelCapabilities, dict]:
+        entry["provider"] = ProviderType.CUSTOM
+        entry.setdefault("friendly_name", f"Custom ({entry['model_name']})")
+        filtered = {k: v for k, v in entry.items() if k in CAPABILITY_FIELD_NAMES}
+        filtered.setdefault("provider", ProviderType.CUSTOM)
+        capability = ModelCapabilities(**filtered)
+        return capability, {}