fix(models): Add missing imports and AuthModel to itm.py

Added pydantic BaseModel import, typing Any, and AuthModel class
for authentication support

models/itm.py

@@ -1,3 +1,12 @@
+from pydantic import BaseModel
+from typing import Any
+
+
+class AuthModel(BaseModel):
+    type: str = "none"
+    credentials: dict[str, str] = {}
+
+
 class RequestModel(BaseModel):
     method: str = "GET"
     path: str = "/"