Configure mypy to run in virtual environment and fix resulting issues (#989)

For some time I've noticed that my IDE is reporting mypy errors that the
pre-commit hook is not picking up. This is because [mypy
mirror](https://github.com/pre-commit/mirrors-mypy) runs in an isolated
pre-commit environment which does not have dependencies installed and it
enables `--ignore-missing-imports` to avoid errors.

This is [advised against by
mypy](https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-library-stubs-or-py-typed-marker)
for obvious reasons:

> We recommend avoiding --ignore-missing-imports if possible: it’s
equivalent to adding a # type: ignore to all unresolved imports in your
codebase.

This PR configures the mypy pre-commit hook to run in the virtual
environment and addresses the additional errors identified as a result.
It also introduces a minimal mypy config into the `pyproject.toml`

[mypy errors identified without the fixes in this
PR](https://github.com/user-attachments/files/15896693/mypyerrors.txt)

kasa/tests/test_device.py

@@ -6,6 +6,7 @@ import importlib
 import inspect
 import pkgutil
 import sys
+from contextlib import AbstractContextManager
 from unittest.mock import Mock, patch
 
 import pytest
@@ -161,7 +162,7 @@ async def _test_attribute(
     dev: Device, attribute_name, is_expected, module_name, *args, will_raise=False
 ):
     if is_expected and will_raise:
-        ctx = pytest.raises(will_raise)
+        ctx: AbstractContextManager = pytest.raises(will_raise)
     elif is_expected:
         ctx = pytest.deprecated_call(match=(f"{attribute_name} is deprecated, use:"))
     else: