[loop-cycle-538] refactor: remove dead airllm provider from cascade router (#459) (#481)

src/infrastructure/router/cascade.py

@@ -100,7 +100,7 @@ class Provider:
     """LLM provider configuration and state."""
 
     name: str
-    type: str  # ollama, openai, anthropic, airllm
+    type: str  # ollama, openai, anthropic
     enabled: bool
     priority: int
     url: str | None = None
@@ -308,15 +308,6 @@ class CascadeRouter:
                 logger.debug("Ollama provider check error: %s", exc)
                 return False
 
-        elif provider.type == "airllm":
-            # Check if airllm is installed
-            try:
-                import importlib.util
-
-                return importlib.util.find_spec("airllm") is not None
-            except (ImportError, ModuleNotFoundError):
-                return False
-
         elif provider.type in ("openai", "anthropic", "grok"):
             # Check if API key is set
             return provider.api_key is not None and provider.api_key != ""