Replace pytest-beartype-tests with pytest-beartype

[adamtheturtle]

Changes

• Replace pytest-beartype-tests with pytest-beartype 0.3.0.
• Pin Beartype 0.23.0rc2 because the plugin requires 0.23.0rc0 or newer and no final 0.23.0 release is available yet.
• Enable checks for test functions and fixtures.
• Enable package checking for vws.

Validation

• uv lock --check (with pinned uv 0.11.7 for Literalizer).
• Local pytest suite: 467 passed in 118.04s (0:01:58).
• prek run --files on the changed source/configuration files passed.