Break tool config schema import cycle

nanobot/config/schema.py

@@ -4,10 +4,10 @@ from __future__ import annotations
 from pathlib import Path
 from typing import TYPE_CHECKING, Any, Literal
 
-from pydantic import AliasChoices, BaseModel, ConfigDict, Field, model_validator
-from pydantic.alias_generators import to_camel
+from pydantic import AliasChoices, ConfigDict, Field, model_validator
 from pydantic_settings import BaseSettings
 
+from nanobot.config_base import Base
 from nanobot.cron.types import CronSchedule
 
 if TYPE_CHECKING:
@@ -18,12 +18,6 @@ if TYPE_CHECKING:
     from nanobot.agent.tools.web import WebToolsConfig
 
 
-class Base(BaseModel):
-    """Base model that accepts both camelCase and snake_case keys."""
-
-    model_config = ConfigDict(alias_generator=to_camel, populate_by_name=True)
-
-
 class ChannelsConfig(Base):
     """Configuration for chat channels.
 
@@ -320,8 +314,8 @@ class ToolsConfig(Base):
     """Tools configuration.
 
     Field types for tool-specific sub-configs are resolved via model_rebuild()
-    at the bottom of this file to avoid circular imports (tool modules import
-    Base from schema.py).
+    at the bottom of this file so tool config classes can stay next to their
+    tool implementations.
     """
 
     web: WebToolsConfig = Field(default_factory=lambda: _lazy_default("nanobot.agent.tools.web", "WebToolsConfig"))