Break tool config schema import cycle

nanobot/config_base.py

@@ -0,0 +1,15 @@
+"""Shared Pydantic base model for configuration DTOs.
+
+This module intentionally lives outside the ``nanobot.config`` package so
+runtime modules can define local config DTOs without importing the full root
+configuration schema.
+"""
+
+from pydantic import BaseModel, ConfigDict
+from pydantic.alias_generators import to_camel
+
+
+class Base(BaseModel):
+    """Base model that accepts both camelCase and snake_case keys."""
+
+    model_config = ConfigDict(alias_generator=to_camel, populate_by_name=True)