test: check decorator typing statically instead of with typeguard

[jd]

typeguard existed for exactly one test: TestRetryTyping asserted at runtime
that @Retry preserves the decorated function's type. That check was weaker
than it looked. check_type() cannot inspect a function object's signature at
runtime, so 'check_type(with_raw, Callable[[int], str])' only ever confirmed
the object was callable -- it would have passed just as happily on a wrapper
that took different arguments or returned something else.

The real guarantee comes from the WrappedFn TypeVar in the overloads, which
is a static property, so check it statically. mypy already runs strict over
tests/, and the annotations here catch strictly more than typeguard did:
the positive cases pin the signature structurally, and the negative case
would fail if @Retry ever decayed to Any, because warn_unused_ignores turns
the then-dead ignore into an error.

Also fixes a copy-paste bug: with_constructor_result was assigned from
with_raw(1), so the @Retry(...) path's result was never checked at all.

Drops the typeguard dependency, which had already cost a round of test
breakage on its 3.x release.

Co-Authored-By: Claude Fable 5 noreply@anthropic.com

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-08-05 09:37 UTC · Rule: default · triggered by rule autoqueue
• ✅ Checks skipped · PR is already up-to-date
• ✅ Merged — 2026-08-05 09:38 UTC · at 6ceafc0ef6bc563d582e3123f4ab0988d9656194 · squash

This pull request spent 8 seconds in the queue, including 1 second running CI.

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  • test: check decorator typing statically instead of with typeguard #673