replace typing module with native collection types

[Ebraam-Ashraf]

Fix #110

Replaced all deprecated typing module aliases across core.py, df.py, and reader.py with their native Python equivalents, as the project targets Python ≥ 3.10 which fully supports them.
This includes switching things like typing.List, typing.Dict, typing.Tuple to their built-in forms,
replacing typing.Optional[X] with the X | None union syntax,
and moving Iterator, Callable, Mapping, and Hashable to collections.abc where they belong.
typing.Any and typing.TYPE_CHECKING were kept from typing as they have no native equivalents.
The changes were applied using pyupgrade --py310-plus to ensure consistency and correctness.

also i ran the existing test suite after the changes to confirm nothing was broken.

[alxmrs]

LGTM, thanks for your contribution!