fix: Pin beartype <0.22.3 to avoid Poetry marker parsing error

Beartype 0.22.3 (released Oct 23, 2025) introduced rc version exclusions
in its requires_python field (!=3.14rc1,!=3.14rc2,>=3.10) which causes
Poetry to fail with 'Invalid marker for python_full_version' error.

This change pins beartype to version 0.22.2 which doesn't have these
problematic markers, allowing Poetry users to successfully resolve
dependencies.

Fixes #2257

Co-authored-by: Jeremiah Lowin <jlowin@users.noreply.github.com>

pyproject.toml

@@ -18,6 +18,7 @@ dependencies = [
     "openapi-core>=0.19.5",
     "py-key-value-aio[disk,keyring,memory]>=0.2.6,<0.3.0",
     "websockets>=15.0.1",
+    "beartype>=0.22.2,<0.22.3",
 ]
 
 requires-python = ">=3.10"