chore: update pytest-asyncio uvloop configuration (#251)

# Summary

Update the test suite’s uvloop integration to align with
`pytest-asyncio`’s loop-factory direction ahead of Python 3.14 policy
deprecations. The shared pytest configuration now uses the hook-based
uvloop setup only, matching the repository’s `pytest-asyncio>=1.0,<2`
requirement.

# Changes

- **pytest-asyncio loop factory hook**
- Keep `pytest_asyncio_loop_factories(...)` in
`/home/runner/work/plugboard/plugboard/tests/conftest.py`
  - Configure uvloop via `uvloop.new_event_loop`

- **Remove obsolete compatibility fallback**
- Drop the conditional `event_loop_policy` fallback for older
`pytest-asyncio` releases
- Simplify the hook implementation now that the project locks to
`pytest-asyncio 1.x`

- **Focused coverage**
- Keep
`/home/runner/work/plugboard/plugboard/tests/unit/test_conftest.py`
- Update it to validate only the supported hook-based uvloop
configuration path

- **Branch maintenance**
- Merge `origin/main` into this branch and resolve the resulting
conflict in `/home/runner/work/plugboard/plugboard/tests/conftest.py`

- **Validation**
  - Ran `make lint`
  - Ran `make build`
- Ran `uv run pytest -rs tests/unit/test_conftest.py
tests/integration/test_component_event_handlers.py`

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: toby-coleman <13170610+toby-coleman@users.noreply.github.com>

Author: Copilot

tests/conftest.py

@@ -1,6 +1,7 @@
 """Configuration for the test suite."""
 
 from abc import ABC
+import asyncio
 import multiprocessing
 import os
 import typing as _t
@@ -20,10 +21,10 @@
 from plugboard.utils.settings import Settings
 
 
-@pytest.fixture(scope="session")
-def event_loop_policy() -> uvloop.EventLoopPolicy:
-    """Set uvloop as the event loop policy for the test session."""
-    return uvloop.EventLoopPolicy()
+@pytest.hookimpl(optionalhook=True)
+def pytest_asyncio_loop_factories() -> dict[str, _t.Callable[[], asyncio.AbstractEventLoop]]:
+    """Configure pytest-asyncio to create event loops with uvloop."""
+    return {"uvloop": uvloop.new_event_loop}
 
 
 @pytest.fixture(scope="session", autouse=True)

tests/unit/test_conftest.py

@@ -0,0 +1,10 @@
+"""Unit tests for the shared pytest configuration."""
+
+import uvloop
+
+from tests import conftest
+
+
+def test_pytest_asyncio_loop_factories_uses_uvloop() -> None:
+    """The shared pytest-asyncio hook should configure uvloop factories."""
+    assert conftest.pytest_asyncio_loop_factories() == {"uvloop": uvloop.new_event_loop}