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/fakeprotocol_smart.py

@@ -276,7 +276,7 @@ class FakeSmartTransport(BaseTransport):
                     ):
                         result["sum"] = len(result[list_key])
                         if self.warn_fixture_missing_methods:
-                            pytest.fixtures_missing_methods.setdefault(
+                            pytest.fixtures_missing_methods.setdefault(  # type: ignore[attr-defined]
                                 self.fixture_name, set()
                             ).add(f"{method} (incomplete '{list_key}' list)")
 
@@ -305,7 +305,7 @@ class FakeSmartTransport(BaseTransport):
                 }
             # Reduce warning spam by consolidating and reporting at the end of the run
             if self.warn_fixture_missing_methods:
-                pytest.fixtures_missing_methods.setdefault(
+                pytest.fixtures_missing_methods.setdefault(  # type: ignore[attr-defined]
                     self.fixture_name, set()
                 ).add(method)
             return retval