test(ingestor_manager): force gc.collect() after each test to avoid __del__ flake

IngestorManager.__del__ calls asyncio.run(self.shutdown()). Adding
tests/unit/connection/test_pool.py shifted GC timing enough that a
cyclic-referenced IngestorManager instance from an earlier test was
swept mid test___del__, double-calling the patched asyncio mock and
failing the assertion. Deterministic gc.collect() after each test in
this file keeps finalizers scoped to their own test.

tests/unit/managers/test_ingestor_manager.py

@@ -1,3 +1,4 @@
+import gc
 from unittest.mock import AsyncMock, MagicMock, call, patch
 
 from pytest import fixture, mark
@@ -15,6 +16,18 @@ metadata = {
 }
 
 
+@fixture(autouse=True)
+def _collect_garbage_after_test():
+    # ponytail: IngestorManager.__del__ calls asyncio.run(self.shutdown()); if a
+    # cyclic-referenced instance from a previous test is swept mid-test by the
+    # generational GC, it can double-call whatever asyncio mock happens to be
+    # patched at that moment (e.g. test___del__). Force a deterministic sweep
+    # after each test so finalizers run in their own test's scope. Upgrade path:
+    # only needed if IngestorManager stops relying on __del__ for cleanup.
+    yield
+    gc.collect()
+
+
 @fixture
 @patch('ingestor.managers.ingestor_manager.DataManager')
 @patch('ingestor.managers.ingestor_manager.ResourceManager')