types_parser: NamedTuple, __new__-only classes, NewType and type aliases cannot be wired #571

This was generated by AI during a pre-4.0 audit of main at 9cd88e7.

Observation (reproduced)

• class NT(NamedTuple): a: A and Factory(NT) fail with "Argument a has no usable type annotation". Hints come from get_type_hints(creator.__init__) (types_parser.py:110), which is object.__init__ here, while inspect.signature reads __new__. Same for any class that defines only __new__. The message is wrong too: there is an annotation.
• UserId = NewType("UserId", int): a provider with bound_type=UserId resolves via resolve(UserId), but def f(uid: UserId) fails with "no usable type annotation" (types_parser.py:51 accepts only isinstance(type_, type)). Same for PEP 695 type X = ... aliases.
• Suspected, not reproduced: a creator returning A | B gets bound_type=None and is skipped at registration with no warning. Verify.

Cleanup in the same file

hasattr(type_, "__metadata__") should be get_origin(...) is Annotated; hasattr(creator, "__init__") (:109) is always true; the branch at :44->54 is unreachable (None | None handled at :23); narrating comments at :27,33,47,129-130,140.

Acceptance

Failing tests first for each type form; the "no usable type annotation" message only appears when there is none.