tests: remove minimal conftest to validate atexit/weakref cleanup path

tests/conftest.py

@@ -1,28 +0,0 @@
-"""Minimal test session cleanup to prevent hanging background servers.
-
-This keeps the test suite simple while ensuring any stray embedding server
-processes are terminated at session start and end.
-"""
-
-import subprocess
-
-
-def _kill_embedding_servers() -> None:
-    patterns = [
-        "hnsw_embedding_server",
-        "diskann_embedding_server",
-        "embedding_server",
-    ]
-    for pat in patterns:
-        try:
-            subprocess.run(["pkill", "-9", "-f", pat], timeout=2, capture_output=True)
-        except Exception:
-            pass
-
-
-def pytest_sessionstart(session):
-    _kill_embedding_servers()
-
-
-def pytest_sessionfinish(session, exitstatus):
-    _kill_embedding_servers()