Avoid eagerly evaluating annotations

[JelleZijlstra]

There are various places in the stdlib where we access the .__annotations__ attribute. Under PEP-649 / PEP-749, this now forces evaluation of lazy annotations. We should avoid evaluating annotations where it is not necessary.

For example, currently typing.Protocol evaluates its annotations at protocol creation time.

Linked PRs

• gh-132493: Support deferred annotations in Protocols #132494
• gh-132493: lazy evaluation of annotations in typing._proto_hook #132534
• gh-132493: Avoid eager import of annotationlib in typing (again) #132596
• gh-132493: Avoid eager evaluation of annotations in @reprlib.recursive_repr() #133411
• gh-132493: Remove __annotations__ usage in inspect._signature_is_functionlike #133415
• [3.14] gh-132493: Remove __annotations__ usage in inspect._signature_is_functionlike (GH-133415) #133796

[JelleZijlstra]

Other cases from a quick audit:

• typing._proto_hook eagerly evaluates annotations. Looks like this could trigger on code like isinstance(X, SomeProtocol) where X has deferred annotations. It doesn't need to know the value of the annotations, only what keys exist.
• inspect._signature_is_functionlike looks for the presence of annotations to decide that something is functionlike. Maybe it should look for __annotate__ instead?
• pydoc in two places looks for the presence of annotations for something with lambdas that I haven't fully deciphered
• reprlib.recursive_repr creates a wrapper function that inherits __annotations__. It should probably use __annotate__ instead.