refactor: centralize type aliases in types.py and simplify crud layer

src/fastapi_toolsets/schemas.py

@@ -1,10 +1,12 @@
 """Base Pydantic schemas for API responses."""
 
 from enum import Enum
-from typing import Any, ClassVar, Generic, TypeVar
+from typing import Any, ClassVar, Generic
 
 from pydantic import BaseModel, ConfigDict
 
+from .types import DataT
+
 __all__ = [
     "ApiError",
     "CursorPagination",
@@ -16,8 +18,6 @@ __all__ = [
     "ResponseStatus",
 ]
 
-DataT = TypeVar("DataT")
-
 
 class PydanticBase(BaseModel):
     """Base class for all Pydantic models with common configuration."""