Remove global random seed fixture

[SripriyaDevarapalli]

Addresses #1060.

The test suite previously reset Python and NumPy global random state
before every test. This removes that autouse fixture so tests can rely
on pytest-randomly for per-test random-state handling.

The collection-time seeds in pytest_configure are retained because they
are used for deterministic parameterization during test collection.

Tests:

• 190 RNG-related tests passed
• Full suite: 2223 passed, 66 skipped, 1 pre-existing Windows/Python 3.14
  forkserver failure

[gemini-code-assist]

Code Review

This pull request removes the set_random_seed autouse fixture from conftest.py, which previously set a fixed random seed using random.seed(0) and np.random.seed(0) during testing. There are no review comments, and I have no additional feedback to provide.