ty compatibility

[kalekseev]

Let's track ty compatibility in this issue

• run ty on CI typecheck tests with ty #339
• respect return type of __new__ astral-sh/ty#281 - right now ty thinks that field field = UUIDField(default=uuid.UUID) has type () -> UUID instead of UUID. (fixed in 0.0.10)
• Trying to set nullable field to None model.filed = None leads to Invalid assignment to data descriptor attribute `field` on type `Self@method` with custom `__set__` method
• ArrayField(CharField()) results in list[list[str]] field type instead of list[str]